Even for over-clocking, water cooling is seldom 'worth it' and is really only even necessary as you approach the extreme end:
http://www.kitguru.net/components/leo-waldock/air-cooler-challenge-7-way-round-up/
And I say this as an avid 'water-works' person
That said, both of those are nice coolers and if you have the room then going for the bigger one is nice as it dissipates more heat more efficiently, and as a result can keep fans running at lower RPMs.....so it's quieter.