I too find some of the default KDE apps to be annoying and cluttered in comparison to many Gnome apps, but things have certainly improved. I'm anxious to play with Amarok again to find how easy it is to get it to what I want in a music player: small with play/pause/next/etc buttons, volume bar, and a playlist, that's it. Amarok used to be so much prettier IMO, the gray is really boring and mono-colored, but oh well. Of course, the gray part is due to the theme, but I preferred the blue and gray/white/etc theme from the previous Amarok.
Will definitely be interesting to see how Gnome 3 and KDE 4.5/6/7/x compete, and even though I like customizing some things which KDE often really allows you to do, I'm hooked on Gnome's simplicity and sane settings by default objective like, well, Arnold on steroids? =P But will continue to try out KDE every now and then.