I like the view of alltop.com because it allows you to scan the feeds very quickly. But I wanted a customizable selection of feeds and so set about writing http://feedsrus.appspot.com/ on Google App Engine.
The feed entries are cached in memcache in GAE and refreshed every 30 mins. Because of some limits in the number of cycles a request can use, the current implementation doesn’t scale for more than 9 feeds or so. Planning to fetch 9 at a time and use AJAX to load the rest in bits.
UPDATE: I modified the code to use Google AJAX Feed API and removed the part in the server code where I download the feeds. This means that all the GAE needs to do is maintain the user’s feeds in the data store. And of course, it is fast now.
UPDATE 2: Feedsrus now has tabs!