I would recommend Empire: Total War, but not for some time. Buying it now is like playing Russian roulette. *Some* people have experienced no technical problems, but the forums are full of people who are ripping their hair out over all the difficulties associated with getting the game to work for more than 10 minutes. Hopefully, in a few months buying it won't be such a gamble, and when it is working, it is great.
For now, try the Rome: Total War and grab yourself one of the mods like Rome Total Realism, SPQR, and Extended Greek Mod. I've loved the first two, and heard great things about the last.
Best of all, you should be able to pick up the game's gold edition for about $20.