CS3 works on Vista - CS2 didn't. They (Adobe) fixed it with last year's release.

Although I've never done it, or had the need to do it, i thought all versions of PS after v5 could do animated GIFs...?
Yeah, Extended will give you 3D model import, as well as an After Effects-like timeline where you can do animations and special effects but with all your Photoshop tools and filters. If you don't have any use for that, just go with Standard.
Hope this helps - good luck!
-Lew ;-)