Ranchero Software just released NetNewsWire 2.0, the greatest RSS reader out there IMO.
That version brings way too many new features to mention them here (I wouldn't even know where to start), but you can find the list and a bunch of screenshots at Ranchero's.
Congrats to Brent and Sheila! NNW is not only a reference in RSS but also in GUI design. Don't miss it!