Socket AM2+ Phenom II?

Before my PC died (using work PC inb4 "How are you online then?" ), I had a Athlon 64 X2 4200+ on a M2A-VM mobo, which has Socket 939/AM2/AM2+. The mobo is perfectly fine, but the CPU is dead (long story). I'm a bit strapped on cash, so I'm hoping I can just stick with the current rig and go pick up a new CPU rather than getting an entirely new PC with AM3+, DDR3, etc. However, I have really no idea whether it's worth grabbing a Tri/Quadcore for a Socket AM2+. Though I might consider just picking up an older Socket AM2 Dualcore for cheap just to have a computer again, I'm wondering if there's any CPU actually worth doing that with, or should I just save money and upgrade everything?

well, it looks like you don't have support for Phenom II chips on your board, so i would say get an athlon X2 7750, then when you have the money get a new rig or upgrade the cpu/mobo/ram (or could even keep the cpu for a while)

though, the board doesn't support s939 (totally different socket than the AM2/AM2+)

Just because it has the same socket doesn't mean it'll work. Your motherboard needs to have an updated BIOS to support new processors that came out after your motherboard was manufactured. Check the motherboard manufacturers website and find your specific motherboard model, than check the cpu support list to see what you can upgrade to.

It looks like you don't want to drop too much for a new CPU, so i'll recommend either an Athlon 64 X2 7750 or a Phenom II X3 720.
Both are very good processors for their price point.

Edit: If you cant get PhII support via BIOS, I'd go for the 7750.