Turn Based Combat Games

15 years old, but check out Shadow Watch anyway

Here is a review on GameFAQs

And an IGN review if you want a 'professional' opinion

Wasteland 2 - http://store.steampowered.com/app/240760

to lazy to make a clicky

Valkyria Chronicles
and it's a JRPG game.

Shadowrun Returns
Shadowrun: Dragonfall

Omerta - City of Gangsters

Divinity Original Sin best stuff this year
Temple of Elemental Evil
South Park: The Stick of Truth
Blackguards
Expeditions: Conquistador great setting -smt new imo
The Banner Saga - very good as well

If i were u i would start with Divinity then Banner, Wasteland 2, Conquistadors and then other titles

Incubation (you can get it in this collection)
Chaos Gate (can be a bit tricky to run on a modern computer, but it works fine in a virtual Win 98 machine)
Massive Chalice (still in early access, but it looks like it has some potential)
Wasteland 2
Expeditions: Conquistador
Fallout Tactics
UFO: After* series (Afterlight, aftershock, aftermath)
Xenonauts (still have not played this one, but it looks promising)

I can't recommend Fallout: Tactics enough. I love the game. You can choose between continuous turn-based or real turn-based.

Also: Silent Storm

Wasteland 2, Fallout Tactics

Pike and Shot... It has muskets, a kind a gun... And VERY strong AI, it's very hard even on easy :)

Seems Halfway isn't very popular.

Anachronox

I guess Blackguards disqualifies as I've not seen any guns in it as far as I played. It's an interesting take on Tactical RPGs though.
So I'll also plunk in Silent Storm

Frozen Synapse is also supposed to be really good, but never got around to playing that. (So also can't comment on the differences between normal and Prime versions, apart from the obviously different art style.)

Jagged Alliance 2 1.13. Unless you haven't played vanilla JA2, in which case play Jagged Alliance 2 you chump.

First two Fallout games are absolute classic and they are must play. It might be a bit old for your taste, but believe me, it's worth it. Amount of attention to detail is incredible in those games. First one is probably my favourite game of all time. I strongly recommend it.

Dead State and Gorky 17

Expeditions: Conquistador

Halfway

Antisquad

Warhammer40000: Chaos gate

Breach & clear

Frozen Synapse is pretty good as far as tactical turn based fighters go.

new one i won recentrly and from little time i spent in it is really good: MASSIVE CHALLICE (that's a game name format)

Already mentioned, but Valkyria Chronicles is worth a look for sure.

Only ones I know are Valkyria Chronicles, and Metal Gear Acid. Also, Heroes of Might and Magic