Get the FX-6100 and upgrade to a Piledriver FX-8350 8core that will spank at 5ghz when you're ready.
This is probably what i'll end up doing further down the line if Piledriver turns out to be a significant improvement over BD.
I decided to upgrade my PSU and case also so my new build looks like this:
CPU: AMD FX-6100 @ 4.2ghz+ (hopefully)
CPU Cooler: CM Hyper 212+ cpu cooler
Mobo: ASRock 970 Extreme3 AM3+ mobo
Memory: 8GB G.skill Ares DDR3-1600
GPU: ATI Radeon HD 4830 512mb(from previous build)
PSU: Corsair CX500 V2 500w PSU
HD WD 250GB 7200rpm HDD (from previous build)
Case: Thermaltake Commander White
Total comes to just about $400 with the $15 coupon from superbiiz for the CPU.
I dont think my old PSU would handle the new overclocked FX. It only has a 4-pin CPU power connector and I don't think that would handle the amount of power these chips require at OC speeds. Hopefully Ill get at least 4.2ghz with that cooler without setting the atmosphere on fire with temps. Im sure with whatever oc I get it will still be a huge improvement over my old build. Here it is if you're interested:
Athlon 64 X2 5600+ @ 2.8ghz
Gigabyte GA-M55SLI-S4 AM2 nForce4 chipset
Radeon HD 4830 512mb
3GB A-Data DDR2-800
Western Digital 250GB 7200RPM HDD
Sony Optiarc DVD-RW
NZXT Trinity mid tower case
NZXT generic 500w PSU (was included with the case)