On topic: I would have got a Phenom 2 x4 as CPU instead of the FX-4100. Guess they're pretty much out of stock everywhere now though since they stopped manufacturing them a while ago. The 960T from AMD is pretty much the same and you might be able to still find that one. I can potentially be unlocked to 6 cores for some extra juice. Most games probably won't see a difference in performance whether it unlocks or not though.
It should outperform the FX-4100 without being unlocked anyway, as the bulldozer modules aren't as fast when all cores have a heavy load.
If I were you I would get the Phenom II x4 over the FX-4100. The FX here costs around $110 while the Phenom is $125. I would definintely try to save up that extra $15-20 to get the Phenom (unless it is out of stock there.)