ceba, vista runs the way it's supposd to for me as well; i've got a HP DV8230 laptop with a dual core & Nvidia GO 7300 video with 512MB memory, with 1 gig of system ram.
I deleted it after trying it though, because there is no flipping point in having a operating system that takes up over half of a good systems resources just to run, and has DRM so strict that I couldn't play even some of my own rendered animations (still sort of in awe on that one). it went off my laptop, and windows media center 2005 went back on.
There is a laundry list of reasons why Vista is a step in the wrong direction from a consumer point of view; for Poser enthusiasts, I guess the point would be this: you know those long render times you get with Win2k, even longer ones with XP? well, they will be longer than ever with Vista, given the same computer hardware is used as a base for comparison. The less well equiped your computer, the looooonger it will take to do anything.
Given a computer with 64MB of ram, a 500mhz processor, and a 2mb video card, you can run Win2k pro and Poser 6. it will not be the zippiest thing in the world, but you could do it. VISTA requires, at a MINIMUM, a 1ghz processor, a 32MB video card, and 512MB of system memory.
I pass the soapbox back to ceba...