In some situations 3200MHz can offer significantly improved performance: http://www.eurogamer.net/articles/digitalfoundry-2016-intel-skylake-core-i5-6500-review (The Witcher 3 in particular gets a nice boost)
i7 6700 might benefit more than the 6500.

Same story, if not even less significant. Say 2133 Mhz DDR4 is in practice less performing than 2133 Mhz DDR3, and that 2800 Mhz DDR4 delivers the same gain vs 2133 than 2400 Mhz DDR3 was. The main interest are bandwith(, but for that one should aim at 3000 Mhz + ) and a suposedly better energy efficiency. Maybe the gap will deepen with newer controllers, but for the time being, ddr4 is no better than ddr3 for most of us. So imho 3000/3200 Mhz DDR4 is pretty much a possibility to explore id paired to a Skylake i7 6700 (k) - but at a cost - however if it's to take lower speed DDR4, price would be the main driver rather than speed.

one thing about buying fast ram is that if you add $50 - $70 to your ram to get 3200, look at what you'd get by adding that $50 - $70 to your gpu.

Something with Intel i7, NVIDIA 900, 16 GB RAM... (y)

depends. If the budget already includes a 980ti, not a lot since it will only get you a more expensive 980ti , maybe with a nicer cooler. On the other hand, if the 70$ allows youy to jump from a 960 to a 970, or from a R7 to a R9, the gain is much higher. But then one can say the same : between a skylake / ddr4 with a lower GPU, and an Haswell/ddr3 with a better GPU...

The Skylake CPUs are better in terms of heat, right? I read this morning that the previous generation i7s are really quite hot CPUs.

Also, Phc7006, you mentioned the Noctua 92mm CPU cooler (I take it the NH-9L that was one of the choices on the OcUK build I liked to). Do you think that would be enough to keep the CPU running cool enough? Reviews say it is fine, but it always seems to be last in comparison to the other coolers it is tested with. With the 6700k I think it would already be a little cooler anyway, but still.

As for the whether to go 6700 or 6700k, the clockspeed is noticeable different (3.4GHz to 4.0GHz) and the PassMark scores are also quite noticeably different (9938 to 11020). Wouldn't the 6700 therefore be not so good paired with the 980Ti?

Probably should add a few other points. I'm not going liquid cooling. I don't really know enough about it and don't want to risk leaks or having to replace coolant or anything, so I'm sticking with air cooling as I'm familiar with that. As for overclocking, I don't want to be tinkering with it myself (I'd be scared of frying the CPU, RAM or motherboard), so overclocking would be limited to any factory overclocked components or anything carried out and tested by the builder.

Oh, I'm a single monitor user here at home. Don't have the desk space for two monitors anyway. Currently using 1680x1050 but hope to get a new monitor at some point (not in any rush right now though) that is 1920x1080. How would this impact on GPU choices?

There are times where I wish I was more confident in building a PC myself. My current one was a self build project, and I'd spent months researching and waiting for the next reliable GPUs (which turned out to be the Nvidia 200 series) and I had help in doing the actual build itself (I say help, my friend actually did most of it as they knew where everything needed plugging in and such).

Oh, a question on the SSD. What is the recommended usage?

Primary SSD for OS and drivers/device software, then all other programs, games and documents on the secondary drive (which in my case would be a mechanical)? Or do people actually start installing the games that they mainly play or commonly used programs on the SSD too?

Only I'm worried about the limited write cycles on SSDs, but I haven't actually ever heard on anyone who has had an SSD die because of using it too much. Windows must surely have many reads and writes, so having additional space for the SSD to use if and when sectors die is a good thing to keep the system running, so would you not then want to put unnecessary programs and files on it? I was looking at 250GB for the SSD and then at least 2TB on the mechanical.

As for Windows itself, my current machine is Vista Ultimate x64 OEM. I wouldn't be re-using it even if I could (which I can't because it is OEM and bound to my existing motherboard). So I will need a new Windows. Win7 seems too old now, especially with support ending in the not too distant future. Win8/8.1 is a no go as I've heard way too many negative things about it. So it will have to be Win10. I have a few friends who are on Win10 and they seem pleased with it, though I've seen mixed opinion on it here in the GOG forums. However, I don't think I have much choice in the matter, except for whether the standard edition is enough or whether I should go for the Professional edition. Haven't researched the differences in the two different versions yet.
Now that is something I hadn't considered. Sure it would get me a good machine and save me the cost of the higher end GPUs, and then towards the end of the year I could then switch out the GPU for one of the new ones (provided they do deliver the performance increases and are reliable). However, it would mean messing inside my machine, which I'm not overly confident with (but I could always get help with that). But it is definitely another option.

Thanks for the info. Im not looking for the be-all end-all when I upgrade, so sticking with the I5 could be a cost-saver. Now the motherboard.. I know that's going to cost me, if I want any sort of future-proof stuff or expansion slots.
But im not looking to RAID or SLI or dual-boot or anything as confusing as that. Just something that gets this PC out of the GTS250 DDR2 era

OS, drivers, etc. + large / slow-loading programs (Adobe / Autodesk products) + games you play frequently + game save files.

I'm running a 256GB SSD + 2TB HDD combo myself :)

The software for my SSD set a default 10% of drive capacity for "over provisioning".

Current SSDs can potentially survive hundreds of terabytes of total writes: http://techreport.com/review/27909/the-ssd-endurance-experiment-theyre-all-dead
If my 840 Pro were to survive the same number of total writes as the one in that article, at the average amount I've written daily over the past year, it would have a lifespan of around 500 years...
Actual usage probably has less even distribution of writes, so some parts of the drive will likely wear out sooner and reduce the overall lifespan of the drive.

Next time I do a full PC build I think I might drop the HDD altogether.

Then you can easily get a regular, non-k cpu and save some bucks.

at 168x105 a 750ti or 950 is plenty. For 192x108 you could get a max. 960. Anything above is useless blown away bucks

Yes you do, you could easily go linux, mint or zorin.

generally you'd wanna buy into skylake now unless you really know what you're doing. skylake has ddr4 support and m.2 support and other shit. they're also good chips. they're pretty cool and efficient, not using their full advertised TDP in a lot of cases. I'm built on Devil's Canyon and I kind of lament the loss of ddr4.

generally you put your OS and your programs on the SSD. any game you want to load quickly you put on the SSD. SSDs make a huge difference in terms of game load times. huge.
SSDs today are pretty damn reliable. typically speaking, they'll last for more written data than you'll ever write to them.

Hot ? : I7-2700K did run hot, but the piture has gradually been improving since. A 4790k did run 10+ °C cooler under load than a 2700K. With 6700K, Intel uses 14nm , which further reduces temps ( Idle temp 8°C lower, load temp 5° lower in the test I found ). Now, if you OC, temps get up.

NH-9L: in the 2 tests that came up first when I googled it, it was compared to 12 or 14cm coolers. With a single fan, it will be less efficient than a Dark Rock 3 by a few degrees. Add a second 92mm fan , and it's almost equivalent. It's much more compact though ( and matters sometimes, depending of the MB and case ) .What matters however is that even with the Noctua, you'll be 15 to 20° cooler than with the stock cooler ! On the other hand, as I wrote earlier, that is if you don't overclock.

6700 vs 6700k : It's the whole debate between optimum and maximum. The performance differential seems more in line with the difference in turbo clock (4 vs 4.2 Ghz). In some games, it will be barely noticeable, if any. In others, yes indeed you see 10% more fps with a k. But in how many will that matter ? And is it worth paying 20% more for the cpu, when nowadays it's the GPU that matters ?

For what its worth i run an FX-8350 with 16GB of ram and a GTX 970 on WIN10x64 PRO

With that setup i can tick everybox and set every option to full and never dip below 32FPS... my normal in all current gen games is 50+

Not so long ago, the only SSD that one could afford were 64/128GB, meaning you just had enough space for OS (64GB) and personnal folders (128GB). With 250 GB you can aadd some programs. The only thing to avoid is installing / desinstalling all the time if I understand well. I had a 64GB win 7 alone but replaced it with a 500 GB on which I have my OS, my non game long term programs ( openoffice, photo edition etc ) . My documents and pictures are on a specific drive ( as a matter of fact my former system drive ) . Then, aside from that I have 2x1Tb + 1x2Tb in HDD ( the PC is 6 years old and has gone through two "midlife" upgrades. Usually I do an upgrade after 2.5 / 3 years then change the PC after 5 years, here I intend to keep it till I can ). Limited write cycles is a potential issue, if you keep your SSD a long time. early SSD were said to have a useful life of 5 years, and that has gone up. For the ordinary user, that's now 10, 20 or (much) more years... For a business, constant use ( like trading algorithms ) , it might be as little as 6/12 months, just to be safe. In other words , life is conditionned by usage and maintenance practice applicable.

Especially as Microsoft intends to force windows 10 adoption to Skylake users by mid 2017 ( no new update after then). I'm really p....off by the MS practice around 10, and, like many, I suspect it announces something nasty ( the advent of an OS by subscription for instance ). Now is this a reason to comply ? I would tend to say no, but you really need to know what's ahead...

To be economically worth it, you'd need to go for a relatively modest GPU now. Not a 970 ( that's still too serious money, to throw it away after 6 or 9 months .... ) , but a 960 or below, or maybe a cheaper Radeon R7. Changing a GFX is peanuts, just make sure there is enough space in the case ( hence my preference for reasonably sized coolers) , and that your PSU has the right set of connectors or is modular ( since some cards use 6 pin connectors, some 8 pins )

Check the price of H97 / Z97 MBs, not goind for the "gamer exclusive " things. From what I see you can get a Z97 MSI Guard pro or a H97 Fatal1ty Asrock for about 150 CAD.