Feedling is a Windows-based RSS reader that suits well to your desktop. It is a .NET 2.0 app that has been tested on XP and Vista 32-bit, and should work on 2000 as well.
As an RSS reader, Feedling can read a variety of different formats. Currently, it can cope with RSS 1.0, RSS 2.0, RDF and Atom. This is implemented as a plugin-based architecture, so that people can write their own parsers.
In terms of other features, it's pretty simple at the moment. It can read any number of feeds that you want and then chucks a maximum of 10 items onto your desktop, refreshing every 10 minutes.