Lee's logo-fest of Web 2.0
Do you know what each of them does? You ought to!
My favourite is Podzinger who license some smart voice technology to deliver their offering.
UPDATE: Many thanks to Jason Moon for his recommendation of this link: web2logo
. At the site they've got a nice tag cloud to help you contextually navigate the logos according to the theme of the business behind the logo, simple yet smart :-).