"Axis & Allies" analog for PC

I'm looking for a game that plays like "Axis & Allies" or "Risk" (i.e. turn-based combat strategy) that's relatively cheap, runs on a computer that's a few years old, and has half-way decent A.I. The digital version of "Axis & Allies" I found at Amazon is real-time, but I'm looking for something turn-based.

Any ideas? I figure this is the place to ask such a question! You guys know more about such things than I do...

This is what you're looking for - it's the videogame replica of the original A&A board game. The 1UP review they have linked is wrong - look at the user reviews.
The only problem with it is that the AI isn't phenomenal, but I think that may be more of a flaw of A&A classic game design.

You could also check out something like Gary Grigsby's World at War - got very good reviews, and is a few years old now.