Do you miss the old Kubuntu style with KDE3?
This is the same theme I created for the KDE4 QtCurve. You can download this and set it so you can feel it same as the old style.

Steps to install:
1. Goto KDE > System Settings > Application Appearance
2. Now select QtCurve from the "Widgget style" dropdown. If you don't find QtCurve than you need to install it(Ubuntu users can install it by this comamnd "sudo apt-get install qtcurve")
3. Than click on "Configure" button.
4. Now a new window will appear. Click on "Import" button.
5. Now select the downloaded file and click "OK" button to close the window.
6. Now click on "Apply" button in the main window.
7. Done

You should also change the color scheme to make it more perfect. Here are steps:
1. Download Color Scheme file from http://opendesktop.org/content/show.php?content=154278
2. Goto KDE > System Settings > Application Appearance.
3. Than click on "Colors" link from left icons.
4. Now click on "Import Scheme" and select the file which we downloaded.
5. A new Color Scheme will appear. Now click on "Apply" button.
6. Done


That's all.