I've been fighting with Vista for several weeks to try and get a scanner working. There is a hotfix on Microsoft website, that they say will be in service Pack 1.
Prior to the hotfix, the application program I chose would hang if I tried to import using WIA. After the hotfix, I can get the scanner to scan, but it's is very slow.
My problems have been with HP products. I got fed up and decided I wasn't getting my older All-in-one scanner to work, so I called HP Pre Sales support and asked if they had newer product that was Vista capable. They told me the new HP Officejet Pro L 7680 would work, So I went out and bought one. It has the same problems. After spending several hours on the phone with Tech support, I was told they don't have the driver ready for Vista and it will be several months.