You just have to do your homework. Research different block/pumps/radiators available, and take into account that stray water and electricity mix alittle too well.
Water cooling is quiet, efficient but expensive.
Air cooling is loud, inefficient but cheap.
You could consider watercooling an investment in the future. You don't have to replace the whole system if you upgrade, Just the CPU waterblock, which is about the same price as a new air-cooled HSF.
I have a watercooling setup. I'll never go back to air cooling.
<A HREF="http://www.geocities.com/lcars_e/compspecs.html" target="_new">Computer Specs</A>
I had a sammich in my head!
<i>-GIR</i>