Netvibes just released a new update (code named Cinnamon) with new features, new modules, and a better user interface.
I have been using Netvibes for a couple of months, and I use it constantly. I tried more RSS readers than I can count, and I hated all of them. Prior to Netvibes, I could not find any RSS readers that worked better than than the RSS functionality built into Firefox. The beauty of Netvibes is that they manage to cram a bunch of feeds on the screen, but organize it in a way that never seems overwhelming or cluttered. I can see all of the posts from more than a dozen blogs without scrolling, mouse-overs give me the first couple of sentences, and I can chose to read any post within the Netvibes interface or natively as a new tab in Firefox. Almost everything is configurable; I can have multiple tabs; and the content is easily organized by dragging and dropping.
Netvibes has also integrated a number of very useful modules. Michael Arrington uses it daily for one stop access to a variety of web services. I can see my unread Gmail messages, my delicious bookmarks (including sort by tags), the front page stories on Digg, the weather and more from a single page.
The best part is that I rarely have to wait on anything. Quick, configurable, intuitive, and easy to use ... everything I want in a web app.