Get the rampage if you plan on doing watercooling (I don't recommend watercooling, the money is better spent on a second video card).
I have a Asus P6TD deluxe which is about the same as the P6T Deluxe V2. They are good mobos, but the second dual slot video card is a little cramped against the case/usb/audio leads along the bottom of the board.
I have an x-fi titanium sound blaster I removed because the drivers were such a pain. Onboard sound on the asus boards is very good.