The biggest problem is that manufacturers regularly change their chipsets and on-board designs without notice and without incrementing the model number. So you might read someone's report online about it working out of the box, only to find your one is a completely different device. Wireless networking kit is notorious for this!
On a related note, a friend of mine recently bought a high-end ABIT motherboard after determining that all of the components should work correctly with Linux.
As it turns out though, the version of SATA controller documented on the website AND the manual that came with the board were different to the one actually on board. Not fun.
Alec
I usually stick with SCSI or basic PATA for hard drives for that reason. After being burned with promise of a Promise controller (back when they were new and hip and fast) I've since stuck with what I know is good; SCSI for power users, Standard PATA for anyone else (and a select few "mature" Ultra100/133 PATA chipsets too).
SATA is probably OK (it will no doubt mature) but I know for *sure* that SCSI (U160/U320) is going to be better AND that Linux will drive it 100% *today*. SCSI kit costs a bit more (ok, a lot more), but for me time is money (yadda, yadda...) and the extra outlay pays for itself very soon after the credit card stops smouldering :P
James -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
