Version:            (using KDE 4.2.1)
Installed from:    Ubuntu Packages

Speaking from personal experience, the tabs in System Settings are difficult to notice if one doesn't already know where they are. The two grays blend right in with the background, and the eyes are drawn to either the icons or the search box with their clean white backgrounds and colorful icons. I must have spent a good several minutes trying to find further configuration options before I noticed the tabs, and my eyes are perfectly fine.
In addition, when I am looking for a setting, it is inconvenient to keep switching between the tabs. Not only are they small targets to hit, but having one tab open means I can't scan the options in the other.

So, I propose that we nix the tabs altogether and keep all the options on one big page. The advanced settings already have their own heading, and there isn't a need to separate the two groups.

Just some usability tweaks.