Go for this PC:
http://www.bestbuy.com/site/HP+-+ENVY+Desktop+-+10GB+Memory+-+2TB+Hard+Drive/6890905.p?id=1218810615070&skuId=6890905 This PC has one of the latest Intel architectures (CPU's) so it should be (in theory) pretty fast! Intel usually make better CPU's than AMD (not so power hungry, slightly faster clock speeds).
There's not much difference between the GPU's. Both have the roughly the same specifications. I'd personally go for the Radeon but the Nvidia is pretty good too.
Both have the same speed RAM and the same amount of RAM. I have 6GB in my PC, I doubt you'd need all 10GB to be honest :p
Wireless Card and Network card seem good.
Apart from that, both PC's are good. But I'd go for the one with the Intel i5 CPU!
You should buy a Solid State Drive (SSD) though

They load stuff way faster than a Hard Drive, so you can load up games quicker, load up Windows quicker, scan your computer quicker.. theyre just generally amazing! You can get a 120GB one for around $80. You may think it's a lot of money, but once you have one, you'll never run just a HDD ever again! They're EPIC!
e.g:
WITH SOLID STATE DRIVE:
Time to start up Windows 7 - 28 seconds.
Time to start up Halo - 7 seconds.
Time to scan SSD (using 80GB) - ~ 5 minutes.
WITH HARD DRIVE:
Time to start up Windows 7 - 1:23 minutes.
Time to start up Halo - 33 seconds.
Time to scan HDD (using 80GB) - ~ 25 minutes.