X2 3800 -152
X2 4200-187
X2 4400 - 231

Which has the best bang for the buck?

Best bang for the buck is none of those. Best bang for the buck is a Core2 Duo E6300. $193, and when overclocked it pwns an FX-62. When not overclocked it pwns ALL of the processors you mentioned. But if you want to know which one of THOSE processors is best bang, its the X2 4200.

MetalX is quite correct in both his statement. If you are hellbend on getting an AMD, wait a few months (upto a year) for AMD to release a better CPU.

Regards,

Korrupt

I asked for one of these. I already have a 939 board. I just want a new processor. Would I see a performance increase with the 4200 or 4400 over my 3700 that I will use for video editing?

Would I see a performance increase with the 4200 or 4400 over my 3700 that I will use for video editing?

If that application happens to be multi-threaded, yes. Look at a few review sites & look for the video rendering sections of their articles.

Will my Zalman CNPS-7000B-CU work on the 4400 or do I need a new one?

Yes, the Zalman CNPS-7000B-CU will work fine.

Is there a better one than that?