I have a iSight camera for some months now, and except for the occasional video chat, it pretty much stays there at the top of my TiBook.
The killer feature for me is that they support scanning the barcodes of CDs, DVDs and books with your iSight. The ThinkSecret article mentions another app with the same capability, Booxter, but a not-as-perfect implementation as Library 3.0.
The screenshots of this app seem very nice. Just hope they deliver it soon. I need to catalogue my growing 300-plus DVDs collection.