The original Medieval: Total war was way better in terms of the campaign map strategy I felt. They tacked too many pointless things on to that part of the game in the later sequels, which make it way less fun. Plus the political/alliance system they have now just doesn't work very well. Sure the graphics kind of suck now, but that matters alot less to me. Then again, as I just said, I'm not really playing it for the RTS element at all. You probably have a different perspective on what's important.
I also reccomend: Warcraft 2 and 3 (assuming you haven't already played them), and Warhammer 40k: Dawn of War.
