Here are two very interesting posts on the question of Feed Readers:

Glassdog asks “What’s wrong with Feed Readers”
Rasterweb talks about “More aggregator maddness”
Info Freako

This is of more than passing interest to me of course, as it relates to the design ofmy Blog Reader: BlogBridge. Some of the ideas mentioned here are already planned for BlogBridge, but there are lots of good tidbits to insipre further work!