Yeah, I'm usually not into RTS to much. World In Conflict is the only one I can stomach.
Speaking of which, are there any TBS games on Steam?
Civilization III and IV are on it, you can pre-order V as well.
There's Space Empires, which is a turn based strategy game in space where you have to build your own units, if you're into that sort of game (I don't really enjoy them, Alpha Centauri being the exception, but I know people who do). Speaking of Alpha Centauri, you can pick it up on Amazon or E-bay for a couple of bucks (the expansion pack is a collector's item and goes for a lot more though). I've been able to run it fine on Windows XP with a little tweaking, I haven't tried it on Windows 7 yet though.
Then there's the X-COM series, which are turn based tactical games, and the Total War series as well, which has a turn based campaign style mode. Battles are fought in real time although you can auto-resolve them which turns the game entirely into a turn-based game.
Fallout 1 and 2 also use VATS exclusively which is a sort of tactical turn based combat system based on action points.
