I also asked this question recently with the additional constraint that I don't run KDE or gnome. Since you run KDE you have more choices, may I suggest you search on sourceforge.net and freshmeat.net.
In the meantime, I have come across two very nice readers. One is curses based, called Snownews. If you like console apps like mutt, snownews will rock your world.
If you like something more modern, bottomFeeder from Cincom is very unusual (because it was written in SmallTalk) and although it's a little buggy and very far from perfect, it has many nice features and once you learn its limits it seems to behave reasonably well.