If you have never tried Civ, Marshall, then I highly recommend you do. It's got a lot in common with total war. Except the battles. I know that's a lot. But by compensation it does have very competitive AI, nice diplomacy and generally excellent gameplay. You can't play it looking for historical realism, but if you love history, you may get a lot of joy from the scope and richness of the historical flavour.

I have not read much good about Civ5. If you want to try Civ, I'd say start with Civ4, ideally with all the expansions.