I've used a few feedreaders (GreatNews, Feedreader, RSSbandit) and flirted with several more. In the end, I keep coming back to using Firefox with the Sage
add-on. While Sage doesn't have all the bells & whistles some newsreaders come with, I can't say I miss them all that much. (And it does do folders.)
In the end, I gave up on wanting one tool to do it all. For me, the ideal newsreading/web research/archiving setup is the following combo:
Firefox + Sage + ReadItLater + Canaware NetNotes + CintaNotes
There's a few other items in my "keeping up" toolkit, but the above five handle the "web part. "