Toolbars are meant to allow the user to quickly find the most used functions of an application. Due to low icon count, they can find the right icon within a split second.
KDE toolbars currently look like they are jampacked with as many icons as possible. This makes these toolbars effectively useless, because they have the same problem as the dropdown menus have: You need to work your brain and spend time to find the icon you are looking for.
Crammed toolbars are missing their goal: quick access to a few of the most used functions of an application.
I always configure my KDE to have useful toolbars, like you can see on the screenshot. I hope that KDE 4 will have useful toolbars by default.
See also the bugreport 67207 on https://bugs.kde.org/show_bug.cgi?id=67207
Please vote for this KDE-Look entry and the bugreport if you agree on cleaning up the KDE toolbars!