Yes, water cooling is very viable for the average joe, and if you do it right, there's nothing to really worry about so disregard the naysayers who believe you will destroy your whole computer. Hell, just last night I was draining/filling the system and during that time one of the tubes got knocked around on the system and came undone spilling a fair amount of water onto my mobo and 6800GT...but since I use doubly distilled water I just let it dry out and the system is back on running perfectly. Point of the story: just make sure to get a fillport =).
Either way, the Koolance systems, though just kits and thus are not near as fun, are entirely self contained and pretty much incapable of leaking or getting screwy.