Re: Old question...new answer? Sata drive using XP?
No. SATA is native on the chipset now, and will install fine. Just be sure to set your BIOS to AHCI instead of IDE mode so that you can access things like Native Command queuing (NCQ) and such. They offer performance benefits that IDE mode can't accomplish.
As long as you build your system with a solid name brand power supply, building your own system these days is a solid experience.
Also, I see very little reason to continue using XP, as 7 is to the point now that performance wise it will out do XP on 99% of all tasks. If you're worried about compatibility, don't be - 7's compatibility mode is a far cry from the lameness that was in Vista. Get yourself a copy of Windows 7 Home Premium x64 and you'll be rocking a modern, capable system that can still do old things. Besides, if you find something that doesn't work on 7, you can just virtualize in a VM system (Virtualbox, VMWare, etc) without missing out on the new stuff.
XP is also woefully swiss cheesed when it comes to security. You're far better off getting 7 for that reason alone.