My first build

If you haven't bought the products yet consider getting intel over AMD for functionality and performance benefits.

CPU: I5 2500K, I5 2400, I3 2100 (yes it is better than the AMD quad core you chose in gaming.)

MOBO: Look at P67 or Z68 chipsets, the best benchmark would be the ASUS P8P67 Pro.

GPU: Look at the GTX 560/560 TI if possible.

If you are only going to run a Single GPU setup with the GTX 560 and I5 2500k you could get away with a Coolermaster GX 550 PSU, it is a 82% efficiency rating with 44A on the +12v rail.

For a HDD if you don't really use close to 1TB, don't buy a TB just because.