I've got a Canon EOS 300D Digital Rebel. I've loaded the latest Canon Windows XP WIA Driver (5.2.0) - there is no Vista driver listed on the Canon site.
I don't get the "Import using Windows" dialog when I connect the camera, and Windows Photo Gallery doesn't list the camera in the import list (although my Canon scanner is listed).
I have the 350D, and it works just fine, without using any additional drivers, just the built in Vista stuff.However, you do need to change the way the camera communicates with the PC (Twain and WPA).
On the Setup 2 screen, change the Communication setting to the other option (I forget which way round they are).