No problems with P7 or P7 Pro on Vista, and Poser Pro at least works great on Windows 7 (x64) too.
I haven't tried P7 on Windows 7, and haven't bought P8 yet. In spite of what you may have read elsewhere here recently.  ;-)

Blue Echo, if you can get that laptop with Windows 7, or at least with a discount to upgrade to Windows 7, I'd recommend that over Vista. I used to be a die-hard Vista fanboy, but not since I installed Windows 7, which is soooooo much better in so many ways.