Ok, i wouldent go with any of those recommended heatsinks. Before i got mine i did alot of looking around. Heres a great site to get computer hardware. The absolute best heatsink you can get for Athlon 64 is going to be the Swiftech MCX6400 V. It has a copper base, and tons of pins.
For the absolute best CPU fan. I highly recommend the Vantec Tornado! This 80mm fans has 84-CFM. I own both the cpu fan and heatsink i suggested. With this cooling system, you will be able to OC, with propure case cooling setup. This fan is not silent at all, but if you want a cool CPU, this fan is going to help ALOT!
Heres the Heatsink.
Heres the CPU Fan