Swiftech's good, but i've seen those waterblocks used with other cheap-o setups, and have heard horror stories about them cracking and leaking over time
d-tek fuzion is the best block. with the d-tek fuzion and that setup you will PWN. actually if you can, get that setup but with the MCR320 instead. you will see considerable temp drops if you get all hose parts but a MCR320 and a fuzion you will beat air temps while OCed by 20C.