mwb1100 - this is true of many OEM installations of XP, on notebooks anyway. I've been wondering about this myself as my OEM discs are for Compaq (and HP?) and Gateway so I have a wee bit of choice. I've been considering going this route as I think it advisable to actually get a machine with Vista preinstalled (all too soon XP is going to be old news, whether we like it or not, and newer software packages/updates will increasingly optimized for Vista) and to take advantage of some of the new hardware that's available. However, I'd still like to be able to downgrade to XP without having to spend mone on a copy and I'm *hoping* that this will work. I'm just waiting to find out if there are any curveballs that might crop up - BIOS level changes that might render the BIOS recognition feature in XP incompatible with a machine designed for Vista. Yes, I am paranoid (and it shows!).
PS I've been looking at DELL because I can still order a machine with XP preinstalled. However, I would rather have a copy of Vista AND a copy of XP, even if I don't intend to run Vista for a while yet.