I went thru the same thing, And I though of it like this,
I'm always going to leave my computer on, so with water cooling I'd always be afraid as to when I left it on, because it could potentially leak.
Also, A lot of strange people use my computer, How am I to know they wont screw up some gasket or something and my whole computer fries?
The last point that made me stick to water cooling is, it seems easy, but setting it up and maintaining it is just way to meticulous. All the water coolers from what I've seen are pretty computer-ly inclined. I'd stick to a thermaltake big typhoon.
Just remember to lap your heatsink aswell as apply some good thermal compound to give best results with any type of cooling