I know how bad the n64 was at supporting RTS games, but the playstation handled red alert, and civilization very well. So Maybe, since the xbox360 is superior to them it can handle RTS games better maybe. I know that a xbox360's hardware is more than what I have in my PC... Sucks though cause i dont see any RTS on the line-up.
edit: A keyboard and mouse would be great. For games like starcraft, i would use both, but on a game like stronghold i only use the mouse...