Help me with my build please!

These are my components:

AMD Phenom II X4 965 AM3 3.4Ghz
Cooler Master eXtreme Power Plus 500w
Sapphire Radeon HD 7770 GHZ 1 GB DDR5
MSI Computer Corp. Motherboard North Bridge AMD 970 & South Bridge AMD SB950 Chipset ATX DDR3 800 AMD AM3+
Corsair Vengeance 8 GB ( 2 x 4 GB ) DDR3 1600 MHz
Cooler Master 120mm Silent Case Fan 4-in-1 Value Pack
Lite-On Super AllWrite 24X SATA DVD+/-RW
GAMMA Classic Series ATX Mid Tower
WD Blue 1 TB Desktop Hard Drive: 3.5 Inch, 7200 RPM, SATA III

And windows 7 of course.

Anything I can add/change? I'm at $650 with this, I would like to not go any higher.

Oh and a main concern of mine, is 500w psu high enough for this set up?

Thanks, Sam!