Cooling an AM3, water over air?

I am going to get the 955, and plan on over clockin it myself instead of the man. oced 965.
So I was looking for a cooling system cause I would like to crank it up, I am going to be using
the 890FX-GD70 when it comes out for my board so I thought it would be sufficent.

Anyways so the case is a Cm 690 2 Advanced, and I have 6.97 inchs for a CPU cooler, and
I first thought the H50 Hydro would be perfect start for someone who has never did water cooling,
but I wasn't quite sure if it was a good option, I even planned on doing the push/ pull and
modding it up with a 240mm Radiatior, so let me know if you are getting cool temps with the H50.
As far a Air Cooling I only have so much room and the V8 is a little to big, but the Hyper n520 and 620
are what I was looking at as far as cooling goes, but I don't know if I will get as good as temps
over the Corsair H50.
So if anyone has suggestions or comments or recommendations, please feel free to write.
Esp. if its some info on the H50, the only reason I was looking into air instead was I didn't want
it to leak and ruin anything so thats why I would like to hear some testimony's.