May I suggest getting the x2 3800+ instead of the 4400+? It would be much cheaper, and with some easy overclocking can pass 4800+ in speed and performance. I have seen quite a few cases of getting 2.7 ghz(2.4 will reach that of the 4800, and will perform almost exactly the same too). That way you can save money up for a 7800gtx or x1800xt.
Also the Seasonic 600w is supposed to be very good according to tests that were done in tomshardware, and a lot of people around the web are suggesting them. However, a few people in the newegg reviews have had cases where: the 12v rail was really 6v, the psu died after 6 hours of use, and defective fans. Bad batch maybe?