I really was considering getting liquid cooling for my new rig, but from the reviews i've read and just from my opinion, as long as you have a good HSF and high-flow case fans, the differences in temps shouldnt be that great.
Besides, with liquid cooling you have to worry about leakage (which isnt that likely, but is possible), and you need to replace the coolant every so often as it may gunk up or evaporate.