Your broad choices are good, but one comment. I have a Cyberpower (the same company as ibuypower) and it came with a very crappy standard PSU that I had to replace with a Corsair. Were I you, I would either plan to replace it or bump up to a better branded PSU for this build. The PSU is the last place you should cheap out.
Edit* I didnt HAVE to replace it--it was still working ok, but before installing a better graphics card I opted not to trust the lightweight PSU that sometimes made rattling noises when my comp sat at the wrong angle. Aside from that, the computer was decent quality--easily as good as a major vendor.