Most RTS games that I've played had one "ubber" strategy which, once mastered, was basically unstoppable. If you are a serious strategist, that type of game just isn't going to fly. If somebody is aware of a RTS that isn't that way, please so advise but I sure as hell haven't seen one. I've played the entire AOE/AOM line as well as the Blizzard lines. Pretty much the same thing all the way around.
There are many turn-based games that kick absolute ass. Unfortunately turn-based games generally do not translate well via Internet or even LAN. You simply have too much deadtime while waiting for your turn.
My favorite three turn-based strategy games:
- Civ III
- Heroes of Might & Magic (thought 2 was actually better than 3)
- Empire Deluxe (an oldy but an amazingly good game)
Moose