I'd vote the Logitech QuickCam for Notebooks Pro. It's compact, has face tracking/zoom, and is compact. The package includes a handy hard case to stow when not in use. I've deployed over 30 of these at work and they rock for our Macromedia Breeze Collaboration Utility.
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Actually, I think I am going to get the brand new Creative Webcam Live Ultra for Notebook which costs about 100 dollars. It's a brand new webcam. However, I still have doubts whether Creative can match Logitech in webcams. Logitech Quickcam Pro for Notebooks have received good reviews but I do not like the design. Another option would be Logitech Quickcam Sphere which is pretty the most expensive webcam in regular computershops. However, it is quite old webcam and the face-tracking is rumoured to be not so good.