Making a watercooled system where you pick a small radiator just seems foolish to me. The ONLY advantage watercooling has is the ability to move the heat from the CPU into a larger surface: the radiator.
When you only have a little bit of space, it seems like a larger heatsink and fan would be better than trying to divide that same space between waterblock, pump, tubing and radiator.
There's nothing magical about water. It just moves the heat, and it's not even as good as metal.
On the other hand, doing it because it is neat... that's a perfectly valid reason.
