Blogbridge, if you don't know about the application, is a really good RSS/newsfeed aggregator that runs on your desktop. Unlike webservice style aggregators, you have a real GUI with some nice and interesting features. As a Java app it will run on any platform having Java ... I'm running it on my Titanium 1ghz Powerbook w/ OS X 10.3.9. My system is still on Java 1.4.x since Apple hasn't yet released 1.5.x officially.
I first started with blogbridge before v1.0 (which was only a few months ago).
At the time there were many severe problems. GUI interactions were very slow, GUI repaints would often leave empty greyness, DnD operations were a pain, etc. But the UI design showed a lot of promise, and it did greatly improve my morning news-reading ritual. So I stuck it out, and now I'm glad I did.
Over that time Apple has issued a few security or bug-fix updates to Java, but as I said has not made a major JDK version number change. This means that every improvement I see in blogbridge comes from the efforts of the blogbridge team, and not due to improvements in the underlying Java.
Swing Sightings is a showcase for good quality Swing applications. The latest issue is no exception, having a slew of great looking and useful applications.