I've got an MSI K9N SLI board. All works quite well, though Audio and network required workarounds. The NFORCE chipset is a bit of a bug bear at times. Currently I can only run with 1 core for maximum stability. Personally I wouldn't buy an AMD board, I'd go for an Intel set up.

---

MacBook Pro 15" | Mac OS X 10.6 • 2 GHz Intel Core Duo • 2 GB DDR2-667 • ATI Radeon Mobility X1600 128 MB • 100 GB Serial-ATA
Hackintosh | Mac OS X 10.5.6 • 3 GHz AMD Athlon 64 X2 6000+ • MSI K9N AM2 • 2 GB DDR2-667 • NVIDIA GeForce 8800 GT 512 MB • ALC888 Audio • 300 GB Serial-ATA
iPhone 3G • 8 GB