Bit late, I've already ordered the motherboard, it was on special and I got it for cheaper than the GA-EX58-UD3R, AUD$100 cheaper than the UD5 too.
We have a long weekend coming up this weekend coming so hopefully I'll be able to spend a bit of time getting it all working.
I purchased the following:
MB - Intel DX58SO
CPU - Intel Core i7 2.66Ghz
RAM - Corsair TR3X6G1333C9 6GB
VID - ASUS 9800GTX+ 512MB
HDD - Western Digital WD1500HLFS Velociraptor 150GB
HDD - Western Digital WD1001FALS Caviar Green, 1TB
POW - Corsair 520W
MON - Samsung 2333SW
OPT - Pioneer DVDRW
It should make for a pretty powerful DAW at half the price or less of a Mac Pro