A good after market cooler

[Zutarano]

I am going to build a computer and I want to try and unlock the 2 extra cores on a Phenom x2 550.
I have found the Zalman CNPS9500 a very good Cooler and every one saying good things about it. It is $54 AUD and that is reasonable.
What do you recommend though?

 

[pr0phet129]

http://www.frostytech.com/top5heatsinks.cfm

check these out, i got the Zalman CNPS10X Extreme on their recommendation, for my x4 955, Runs fantastically.