Personally, I've never been a big fan of KMenu. It looks ugly when there are plenty of applications in one category, and looks jumbled and hard to navigate. Luckily, there is a replacement that looks nicer, is easier to use, and has more functionality: TastyMenu. This is a three paned menu, with a built in search box, and functions for quickly switching users, session management, or running commands. Because it is a replacement for KMenu, it only works under the KDE desktop environment. In most distros, it is in the repositories under the name 'tastymenu' or it can be downloaded from the Home Page or from KDE-Look.
After it is installed, right click on kicker and select "add applet to panel."

Search or scroll down to find "Tasty Menu" and select it.

This should add it to Kicker. By default, it uses the same image as KMenu. You can now either remove KMenu by right clicking it and selecting 'remove' or have both TastyMenu and KMenu on Kicker at once. Here is what it looks like on my computer: