I need a good turn-based miltary strategy game, Windows or Linux

[SuperDuck]

I need a new game, and I'm open to suggestions.

The big requirement is that it's turn-based. I've played lots of RTS games lately, be it Starcraft or AOE, etc., and while I am looking forward to Starcraft II I would like to get something turn-based so I can really think ahead and actually use some strategery.

Civ III is still one of my favorite games of all time, though I'm looking for something more military based. As the title suggests, I can go for something either on Windows or Linux.

What do you guys like?

EDIT: I'm aware of the new port of Axis & Allies - I haven't tried that yet though I'm a big fan of the board games. (We've got darn near all of the versions..)

[MonkeyBoy]

Wesnoth springs instantly to mind as does Crimson Fields. Tried them?

Also if you are a boardgame player look here (http://www.brettspielwelt.de/Spiele/?nation=en). The Brettspielwelt client works well and can be altered to English.

[Artificial Intelligence]

Dominions 3, it aren't free, but it's one of the best Strategy games I've tried (if you like fantasy); http://www.shrapnelgames.com/Illwinter/Dom3/1.htm