Why not the Thermalright Ultra 120 Black? It looks amazing, comes with 2 brackets to install 2 additional fans, and fits socket AM2 fine. In the event the backplate on your mobo is plastic (As many higher end producers are doing to save on costs thanks to AMD's bad showing) you could buy a simple thermalright am2 backplate at around 7 US Dollars or negligible in quids.
The only downside I see is the large size of the Heatsink, and the lack of an included fan, but look at it this way;
The lack of fan seems to imply you can use 2x (for a push-pull config) fan of your choice, ranging from the Impressive Scythe's to the affordable Yate loon's. As for the size, it is a tight fight on my DFI UT 790FX M2R (as the memory slots are real close to the processor, and my OCZ Reaper heatpipes tend to get in the way) but I feel you can make it work on your rig.
Another downside is it's cost, but I'm sure you'll be more than happy with it's performance.
P.S. The older revisions are much cheaper, albeit not as polished (read: pretty) as the black edition
