Benchmark Reviews has recently tested many of the top coolers mentioned in their Best CPU Cooler Performance - Q1 2008 article. All of these coolers were tested with the same fan, to isolate performance, and were in stock form (not lapped or modified).
Keep in mind that your results are going to be different, since fans will vary the final cooling performance.
But i did however once attempting a watercooling experiment involving 2 computers and a a mini-beer fridge as a heat exchanger... it didn't end well...