I like turn based rpgs, but my tastes are pretty picky. First off, not a big fan of traditional jrpgs, where both sides line up in rows on either side of the screen. I like an actual map to move around in a battle. Secondly, I don't enjoy turn based rpgs where resource management between encounters is a huge part of the game. I don't care if the individual encounters are tougher for it, but I enjoy each fight being its own isolated challenge, rather than having to manage health, ammo, stamina, magic etc... over long periods of time and multiple encounters. Any suggestions?

All of these are very good games which fit with the descriptions you mentioned:

Divinity Original Sin part 1 (excellent combat but the story and characterization are a bit weak...the sequel's combat is much worse though, so I recommend sticking with part 1).

Trails in the Sky parts 1 - 3 (good combat and story and characterization).

Trails of Cold Steel parts 1 - 2 (also good combat and story and characterization...and part 3 is coming to PC in English next month).

It depends what is your priority. Combat itself, story, immersion, lore?

Wizardry 6, 7, 8 are turn based, as are most of the Heroes of Might and Magic games. Also:
Albion
Amberstar
Ambermoon
Dragon Wars
Wasteland 1
Fallout 1 and 2
Bard's Tale 1-3 and the remake
Perihelion for the Amiga
Septera Core
Anachronox (Highly recommended - a true gem!]
Superhero League of Hoboken

OP specifically requested tactical map combat. This disqualifies at least half your list off the top of my head, including the awful Anachronox, which isn't even turn-based, it's ATB (real time with wait). That's not to say that I object to any of those games (other than Anachronox) otherwise. Actually, Septerra Core is also ATB, but I don't think it's as bad.

It's hard to say what's "good". I'd second the recommendations of Ancient-Red-Dragon, although I don't have any objections to DivOS 2. I'd also second the recommendations of Fallout1-2.

Filtering my owned gog games by Role-Playing, but leaving out games I consider to be more strategy than role-playing, in no particular order, I see: Temple of Elemental Evil, Shadowrun series, Grandia II (a JRPG, but the combat is not line combat), Arcanum (if you select turn-based combat), Blackguards series, Realms of Arkania series, Gold box and Dark Sun games (although these tend to require excessive resting to replenish spells), Wasteland 2 (1 doesn't have tactical map combat), Neptunia series, The Age of Decadence (not much combat) or Dungeon Rats (not mch story), ATOM RPG, Spiderweb Software games. Also too many games that I haven't played long enough to evaluate yet.

It's interesting that your preferences are actually the opposite of mine. I prefer turn-based RPGs where I *don't* have to worry about moving my characters on a map, and RPGs where resource management between battles is a major part of the game.

In any case, I could mention:
* Ultima 3-6 have maps during combat, and MP regenerates. However, other resources do not, and spells require reagents in Ultima 4-6, plus Ultima 5 and 6 give you limited ammo (though you can do just fine ignoring weapons with limited ammo). Ultima 3 might be the most practical, as the only resources to worry about are food and guild items (which are mostly not used in combat anyway); MP regenerates, there are no reagents, and HP can be restored with spells (though it can be tedious to do so).
* Fell Seal: Arbiter's Mark is likely a good choice, as it looks just like Japanes SRPGs like Final Fantasy Tactics, which fills your preferences (map to move around on during battle and HP/MP are restored between battles)..

It's worth noting that Wizardry 6-8, Dragon Wars, and Bard's Tale 1-3 don't have maps to move around in batlle (well, you can move in Wizardry 8, but your party must stay together). Also, Ultima 7 and later are not suited, as they are not turn based (Ultima 7's combat is actually quite terrible).

(I also note that Wasteland 1 does allow you to move your characters separately during battle, but that option is somewhat clunky as it requires issuing separate disband commands, and you are still limited to 4 parties.)

Also, you could look into roguelikes, where you only control one character but you do have a map to move on even during combat. There is resource management, but it's not unusual for HP and sometimes MP (if such a stat exists) to regenerate with time.

(Non-GOG games that might work include Fire Emblem (series), Shining Force 1-3, Tactics Ogre, Final Fantasy, Disgaea series along with La Pucelle, Phantom Brave, and Makai Kingdom (these games do have item worlds or similar areas where you might have to last 10 floors, but you can skip a floor if you can reach the gate and many of these games give you enough SP for SP conservation to be irrelevant, and you are typically only required to go in once unless you're trying to get strong enough to attempt the postgame).)

For more modern games I'd say you can't go wrong with Shadowrun. Any of them is an excellent choice. Age of Decadence is also a really good though more difficult game.

I really like Legends of Eisenwald. It's more akin to the game you don't like (guys lining up on a grid) and it does have resource management (a bit). But I have to plug the game because I feel like it's an overlooked gem that I really enjoyed ;)

But if you haven't tried them yet I'd definately grab a Shadowrun game and see how that strikes your fancy.

Absolutely play the Divinity Original Sin games, if you haven't. I haven't played Wasteland 2 yet, but it's turn-based. Unfortunately most RPGs are either real-time with pause or action. There's a ton of turn-based strategy games though.

I see no one here has mentioned Spiderweb Software games. Though they are very story heavy, the combat in the Geneforge and Avadon series sound like they might fit what you're looking for. I can't comment on the Avernum series as I haven't played any of those games yet.
(There is a remake of Geneforge 1 in the works, but while it's not out, the original is still very much worth playing.)

Just so nobody thinks I read this and added it to my post after the fact, I did mention Spiderweb Software, but not any specific games.

Shadowrun series recommended. Mutant Year Zero: Road to Eden isn't too bad with the turn-based combat, but the story is pretty weak in comparison.

Oops, so you did. Apologies for not noticing.

Since Spiderweb Software games have been mentioned, don't forget that they have demos available.

I might not call these "the best," but I had a blast playing them. The story, dark tone, setting (The Dark Eye's Aventura), and environmental effects really sucked me in... and I usually don't play turn-based RPGs.

Blackguards
Blackguards II

If I might always suggest Avernum forever?

Look, the games have free demos. Try and buy, you know?

Gold Box games

Disciples of Steel
Nahlakh
Natuk

Last three are not on GOG, though.