If you want a fast system on Virtual Box or on your real machine take a look at this topic:
How lightweight KDE is tying to be?

And while Kubuntu (or Debian) is good for new system I feel that Kubuntu is "heavy" on the resources. So I would advise you to use soemthing more lightweight.
I guess that Debian's KDE "filtered" or even compiled would do the trick. Or something like Arch or any other lightweight distro would do the trick.

To sum it up KDE can be lightweight nad usable on older machines it's just that you have to made it that way.
But if you have coding and distro making skills you can still make your own distro. Or at least start to think in that way. I know I am.

bcooksley wrote:The system tray has to be drawn in a system themed box, otherwise we end up with severe icon corruption unless a hack is implemented which causes Gtk applications to crash ( and the Gtk devs refused to fix it, stating that KDE was breaking the expected behaviour of X with the hack ) The only way around it is to provide a widget without the alpha channel ( which if it used your panel colour would look terrible )

What ? How about using this "hack" for all the people that don't use gtk+ apps at all ? I mean I use them but after reading this I think I will double my tries to run a "Qt4 only" desktop.
Oh and even if we run gtk+ apps the most popular ones (Firefox, Gimp) do not use system tray at all

melkart wrote:I take it that at the moment it is impossible to run KDE 4 with reasonable speed without hardware graphics acceleration, right?

I'd say that's wrong. I've run KDE4 on a machine where graphics acceleration was, to my knowledge, impossible. It wasn't a speed-demon but no slower than KDE3, Gnome, or XP.

bcooksley wrote:The system tray has to be drawn in a system themed box, otherwise we end up with severe icon corruption

like this ?

i definitely prefer this over a frame

* bcooksley would call that a bug, which many other users did also.

If you wish to have a system tray which behaves like that, I suggest you extract the System Tray from KDE 4.1/4.0.

So people yet doesnt understand why plasma was made for -yeah, it was not just created to add fancy superkarama alike gadgets, widgets whatever- it also provides a easy way to personalize adding panels, removing others, adding plasmoids removing plasmoids and stuff, try it and you will see

thats great but why flood with so much eye candy (without option to disable) ???

bcooksley wrote:The size of tray icons is determined by the fd.o spec regarding system tray icons, therefore the size of those is outside the control of KDE.

xfce4.6 is able to scale these icons to even fit 2 in a row; autohide of inactive icons would also be nice

i think autohide is going to be in kde 4.3