Hmm,
Was trying out the new Feedreader version (3.0, beta), and I found out after importing a few feeds that it would keep the proccessor at 100%, all the time. It did respond well enough, untill I tried closing, which did not work until I killed it of in the Task Manager.
After diagnosing the problem a bit more (it would return to this state after only seconds after launching the software), I found out that there was a problematic Feed, from ProjectPath (by 37signals).
When I removed that feed, the program would start running normally again (after a restart).
The only special thing about that feed is that it requires HTTP authentication, which I coult correctly enter into Feedreader, and it could successfully connect and get all the feeds the first time, however, later all feed-updates would stop with the processor at 100%.
I really do hope that you fix this soon, as I really want access to that Feed, and I really do love your new version.
Thanks for everything