Also, Newegg has a deal right now on an ASRock z77 motherboard that has built in WiFi with a free 8GB stick of Corsair Vengeance for $150.00. That's basically what the board costs by itself. Good deal
I missed the mention of the 7950 , and I agree the 300 watt Silverstone would not be adequate . The 450 watt is marginal too , but there is a 600 watt version
The other option for powerful graphics cards is the Bitfenix Prodigy .
Bigger than most mini-ITX cases it can fit an ATX power supply and a decent range of cpu coolers .
Still very easy to move around thanks to the handles