To be honest, unless you're prepared to spend over $150~$200 bucks on water cooling, its probably better to stick with air cooling. Generally speaking a $150 kit can perform up to a Thermalright Ultra-120 (TRUE).
However, if you still insist on going for water, there are some beginners' kits you can look at.
I built my own from parts on Danger Den, and I got the swift tech water block from the egg. Do not get a thermaltake water flow meter, they are a waste of $30 and they leak right of the bat. I am running mine with out a flow meter now, and have it set up with a 655 swift tech pump, kinda over kill, but if I want to include my 4870's in the loop I can. I use tygon 1/2 lines with Ultra fluid XP+ non conductive fluid. I have a auto trans radiator I got from the auto parts store, 12"x12" and a 230 mm fan to cool it. Love this set up, and it keeps my Phenom II 940 overclocked a 3.6ghz stable at 32c-40c at all times.