If your dead set on open loop water cooling, then read the watercooling sticky and learn all about them. It can get very expensive fast and if you don't all the exact right parts and don't fit and test everything properly, hello soggy PC and a very expensive mistake. You've had lots of good suggestion including the tried and true Evo 212 for $30 that will cool most none-overclocked CPU's better than anything else out there, but you're jumping around, so decide what you want first, then learn about watercooling, then decide if you want to do it.