QtCurve is a beautiful and highly configurable style for KDE. It's mature and bug-free, so if you want to give it a try, download the source for KDE 3 from the KDE-Look.org page . Next, install the dependencies:
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The last command as root. Your style should now be installed. To apply it and configure QtCurve, run KControl (hit ALT+F2 and enter kcontrol), go to Appearance & Themes -> Style, and select QtCurve from the Widget Style drop-down list.