Yes, it runs fine on Vista 64 bit. Just got the final code downloaded and installed a couple of weeks ago. (Official MS-Technet Subscription) I haven't encountered any problems with Carrara 5 Pro.  I've also been running Carrara 5 Pro on Windows XP 64 bit for over a year with no issues.

However, there are problems with a lack of stable drivers and utilities. Nvidia's graphics driver is still beta, and it shows. Other hardware support is still under development as well. Some items work great, others still don't have support. Anti-Virus/Firewall/Spyware software is pretty much beta and buggy. Support will improve, but unless you are getting it installed on a new machine, I'd give Vista about 6 months to get the drivers and software compatibility shaken out. If you're technically savvy and can live with / work around buggy beta drivers then go for it, but you've been warned... :)

That said, I do like some of the new interface features and hate the constant permission pop-ups when installing/configuring the system.

Don't know if you use Poser, but Poser 7 DOES NOT WORK with vista. Poser 6 does.  I use Poser for the figures and cheap models, then import into Carrara for final texturing and rendering.