Liferea: I discovered it a few days ago, and I like it a lot, though has occasionally crashed suddenly. I like the "pop-up notifications", and the look and feel. The "Unread" virtual folder is good too.

I was using Akregator, which I also like a lot, but for some reason it sometimes seems to just stop updating its feeds, and sometimes seems to corrupt the files where it stores them. The nice feature of Akregator is its integration with Konqueror - "the add this feed to Akregator" menu.