Guy Kawaski, Will Mayall, and the rest of the folks at Nononina have built a new topic-based RSS aggregator called Alltop. There idea is to display the latest five stories from thirty or more blogs in each topic area. You can drill down to the topic areas that you are most interested in by using the appropriate subdomain URL. My favorites are:
I'm also pretty interested in the Linux topic. I think there could be a market for a Web Development or PHP topic. There's already a Politics topic that probably would be a quick way to catch up on what's going on in the latest news cycle.
I think Alltop is an excellent idea and could be a mobile competitor to Google Reader if they create an iPhone version.