I agree, Phenom II>FX-4100. HOWEVER, if you can go with the FX-8120, its actually very reasonally priced currently. One other critique I would give on your build, is that it would be a good idea to spend a few extra bucks on a 6870 over the 6850, but both are fine.
I'd also consider getting a case without a power supply and a separate one.. More often than not the power supplies that come with cases are garbage.
BTW clutch, Tom's has a first peek at Piledriver with early Trinity Benchmarks, Piledriver is definitely showing promise. http://www.tomshardware.com/reviews/a10-5800k-a8-5600k-a6-5400k,3224.html