For ease of use I'd put the Linux system on its own hard drive. And I'd create at least two different partitions on that hard drive, one for / and one for /home.

With that 320 GB you could also part it into three different partitions and use the third partition for shared files, like for example downloads, music and so on.

Besides, what makes you think that GNU/Linux is a superior operating system? First and foremost, it is different compared to, for example, Windows.

1. DRM-free Trine 2.
2. Windows Explorer hangs up.
3. Windows programs take up to 3 minutes to launch, and that with UAC off.
3a. UAC nagging.
4. Linux-only software.
5. DRM-free Trine 2.

2: Windows Explorer hanging isn't a normal Windows behavior.
3: Programs taking 3 minutes to launch isn't normal Windows behavior.
4: UAC nagging? On Linux providing your password is a way of life.
5: DRM-free : If this is REALLY important to you then Linux might be a good match.

If you're curious about Linux then by all means install it on it's own drive (let the installer worry about partitioning), just be aware that it isn't a solution to most of the problems you listed.

What the crap are you doing to the installation?

Also, UAC, eh? LOL, well, you'll be seeing something similar A LOT more in a Linux based distribution.

DRM being one of the motivating points? Well, I never thought I'd hear that. :)

I think you should try the Windows based installer where you can give it ago without changing partitions. If that works out then you can download the iso and install it in its own partition.

http://www.ubuntu.com/download/desktop/windows-installer

1. Nothing. I reinstalled vista from the recovery partition about a dozen times, choosing to not install various software than might have been causing problems, including an, ahem, extended trial of CS3. Every startup, explorer hangs up and either has the decency to crash automatically or I have to restart it manually.

2. I'm fine with pressing an extra button or typing a password. It's not okay when I launch software and it doesn't launch, or does not properly install because Vista denied registry changes or something and didn't even ask for permission. It is somehow better to know that there is a logical solution to a given problem, even though I may lack the intellectual capacity to reach it, than to know that there is a magical solution, and if the magic does not lolrandomly work then sucks to be me.

3. That, and free software (free as in beer, e.g. Super Flexible File Synchronizer).

Maybe the recovery partition is faulty. Never seen Explorer crash on its own, its usually always a context menu entry, thumbnails extension, some UI addon, AV hang-ups, stuff like that.

Install stuff that's giving you UAC issues outside of system-wide folders.

I like free beer. :D