Which AMD CPU would you choose?

Okay, so I know a lot of people post these threads, but I haven't really kept up with all the new CPU technology of the past 2 years, so I need some advice. I currently run a Windsor 5200+ dual-core with 4GB DDR2 RAM. I'm going to get a new AM3 socket motherboard with 8GB of DDR3 RAM, but I'm unsure of whether to go with a Phenom II X2 555 Black Edition Callisto 3.2GHz or a Athlon II X4 640 Propus 3.0GHz. They are roughly the same price, but one is a dual-core and one is a quad-core.

Most of my high-intensity computing will consist of gaming, but I also do a fair amount of Photoshop and working with really large PDF files. Which do you think I should go with? I have a nice, after-market heatsink and could potentially do some OCing. Some folks say you can unlock a core or two on the Phenom II black edition, but I've no experience with that. Suggestions? Thanks

 

I'd get the 555BE and a good M'board (Asus, Gigabyte) and unlock and o'clock it to 4GHZ, I doubt if you'd really need to get an aftermarket cooler unless you can get all 4 cores over 75% over an extended period.