I stumbled across netvibes this morning. This is very cool. Though Netvibes is currently in early beta, you can create your own web page that aggregates RSS feeds, local weather, gmail, and the ability to add notes to your site (sort of like web stickies. You can drag and drop to arrange things as you like. There is definitely a huge amount of potential here to make this a very compelling tool.
Alas, no Safari support (yet). Firefox for OS X works fine, though.
Looking around a bit more, this seems to be very similar to start.com functionality wise. Start suffers from being a MS sponsored project as well as not having as clean an interface as netvibes.
I also discovered meebo , which is apparently trying to be a web-based IM aggregator (much like I wished that google talk was web-based).
Overall, it looks like commercial grade AJAX apps are starting to take off. And, no, Microsoft, we don’t need your bloated, ill-conceived, proprietary ‘rich client’ software. Thank you very much.