PC Magazine, in an article entitled RSS News Readers Browse for You explains what RSS and News Readers are. They identify the top news aggregators as: FeedDemon 1.0, Feedreader 2.5, NewsGator 1.3 and SharpReader 0.9.2.1. [story via beSpacific]
On the Mac side the best news reader is NetNewsWire. I have my own brief explanation of RSS and News Readers available here.
P.S. If you want a better practice, check out this Ultimate Guide.
