Change to the RAM: This set is actually a lot better than the one outlw pointed to: G.Skill Ripjaws 2x2 GB DDR3 1600 mhz CAS Latency 7
for $110. There's good 1333 mhz ones that are only $5 cheaper, but I think it's worth the extra bit.
I would consider getting the HAF 922
. It's only $80 after rebate, and most consider it better than the Antec 900, though they're both high quality cases.
Second the Samsung F3 suggestion and th Asus P7P55D-E Pro.