Google just announced their new RSS Reader, called Google Reader. It's browser-based (of course) and has similar look n' feel to Gmail. Very Ajaxy. I'll play with it some more and report back later. For now, here's more info from SEW:
"Google Reader is a browser-based application that works with virtually all popular browsers on Windows, Mac and Linux platforms.
Google Reader is "the most comprehensive feed finder available," said Jason Shellen, the Google product manager who spearheaded the development of the program. Comprehensive, yes, but Reader also adheres to Google's trademark simple, easy-to-use design philosophy. "We're trying to find an easier find and subscribe model for feeds," said Shellen.
The program features a Google search box at the top which allows you to search for feeds or do an entire web search. Like most other feed readers out there, Google reader has two panes. The left side displays your reading list and the feeds you've subscribed to, and a preview pane on the right allows you to read feed content.
Content can be displayed by relevance or date. Reader also employs algorithms that learn your content preferences and prioritizes content accordingly. This is similar to the auto-discovery feature for news that's part of the Google Sidebar."