NetNewsWire has been doing that for me for years. I keep 30-40 feeds in a handful of folders. When one of them gets too spammy or boring, I delete it; when I find something potentially useful, I add it. I have never felt the need for some algorithm suggesting even more feeds to read.

I also write a weblog useful to a non-techie audience, and am disappointed and slightly frustrated by how few of those people use RSS. If you want to solve a problem related to RSS, solve that.