Do you want to water cool the whole system, or just the video card?
And also, not being judgemental, please list your main reasons for choosing water cooling and do you have any experience maintaining a water cooled system?
For a processor you really should be looking for something like the Intel® Core™ I5 2500k. This is a quad core processor that will give you great performance in WOW. IF you matched the 2500k up with a P67 board like the Intel desktop board BOXDP67BGB3, which is designed to give you outstanding performance and the ability to overclock your processor if you desire.