I have two water cooled computers that run perfectly well. Both are now QX9650's, one started as an E6600 the other as a P4. I built my first one just over 2 years ago. Currently they are both running 24 hours a day with 100% CPU loads at least 80% of the time, both are clocked at over 4gHz. My temps never go over 60c. Water cooling or better is the only way to achieve this. In the two years I have been running them I have had no failures and no leaks. I doubt I have had to top up the water more than once a year. I used Laing D5 pumps which are pretty much silent, 360 black ice radiators and swiftech waterblocks. I use 6 fans in a push/pull configuration on each radiator, which allows for lower fan speeds and less noise. Swiftech and Dangerden supply about the best water cooling kit, so as long as you avoid the cheaper kits, you shouldn't have problems. One of the best things about water cooling is that the components are easily adapted to any computer you might build, so if you buy the right kit in the first place it will last you for years.