Business 2.0 (subscription required) lists 25 hot Web 2.0 start ups in 5 categories
Social Media - Digg, Last.fm, Newsvine, Tagworld, YouTube
Mashups and Filters - Bloglines, Eurekster, Simply Hired, Technorati, Trulia, Wink
The New Phone - Fonality, Iotum, SIPphone, Vivox,
The Webtop - Jotspot, 30Boxes, 37Signals, Writely, Zimbra
Under the Hood - Brightcove, Jigsaw, salesforce.com,SimpleFeed, Six Apart
17 of the companies are in Silicon Valley, another 2 in rest of CA. Should Arnold take credit?
Update: Jason Wood questions the list. As have many others. When there are so many more Web 2.0 start-ups, any list like this is bound to.