I think that more important question is will Vista be truly OpenGL compatible.
I would expect it to support OGL. But considering we're talking about Microsoft, you can never be sure. One thing is sure - if MS chooses to alienate itself from OpenGL games, they are shooting both us and themselves in the leg. If OpenGL would not be supported on Vista, the SCP crew would definitely either have to learn to code for D3D, and I think fixing all D3D issues would take forever, unless some D3D apt programmers suddenly emerged from some moist hole under a stone in a ground to do that herculean job of bringing D3D code up-to-date. Unless that happens (which is, suffice to say, highly unprobable) I suppose the SCP would actually have no other choice but to drop Windows support (for Vista, that is) and keep supporting NT Windows versions, Mac OS X and Linuxi (Or Linuxes, but Linuxi sounds more like the corect plurar...).
I have no actual information how OpenGL support is/will be executed in Vista version. But considering that SCP crew writes almost exclusively for OpenGL, I very much hope the game will run in OpenGL with Vista.
If it doesn't, I suppose I'll be switching to Linux/keep XP around just for keeping FSOpen running. In fact I may move completely to Linux side anyway, and keep Windows versions around just to play games with them.
Hmm... I'll be seeing if I can make Grand Prix 2 run in Vista...

...drat. Taylor said the same in four sentences... Does anyone have first-hand information about OpenGL and Vista, or even better, about Freespace Open on some beta/RC Vista?