I've had good luck with the Fujitsu S510 ScanSnap scanners. They're fast, color, multi-page, duplex, sheet fed units. They come with a copy of Acrobat Standard and they've been holding up well in law offices where they get heavy use.
The current (updated) version is the ScanSnap S1500.
http://www.fujitsu.com/us/services/computing/peripherals/scanners/scansnap/scansnap-s1500.html
Note: I've only used them with Windows XP so I haven't tested how well they interface with Vista. There is also a model S1500M for Mac's.
The only downside that comes to mind is that they tend to run a lot of background processes, and should only be used with relatively new/fast computers.
-ENO