If you liked the Total Annihilation series, you might want to give Supreme Commander a shot. I know World in Conflict just released a demo and is releasing on Sep 18 and is definitely a great RTS you should enjoy. Nothing beats Company of Heroes as well, that is a great WW2 RTS.
Depends on what you're really after. You got the powerhouse of em all which is WoW, and you've got other options which I also suggest, Lord of the Rings Online. Theres a couple of runner ups coming out soon, the prematurely slated Tabula Rasa, Warhammer Online and AOC for next year. Theres a bunch of others but These are going to be major contenders.