I'll be running Window 7 64-bit and read somewhere that the BIOS may need updating. I don't know the first thing about this so would hopefully like a board where this isn't necessary. I think this does that, but I'm not 100 per cent. Also, the look of the board is very important as the side of the case will be windowed to show off the parts.
The 750W version of that PSU has been negatively reviewed at Jonnyguru (twice) and Hardwaresecrets. All the other PSUs in the range are based on the same design, so the 550W GX will have the same problems, which are out of spec ripple on the 3.3V rail, lower efficiency than stated, and inability to deal with heat.