Just a quick screenshot to show how drop shadows look in Linux. The eyecandy, ahem, I mean, useful visual cues that Mac OSX and Windows Vista tout are now easy to enable in KDE. I just installed Kubuntu, added a line or two to my xorg.conf, and turned shadows on in the GUI. Very slick.
I've got a little 1ghz computer and a very old ATI card. The screen refresh rate when sliding a window around is a little slow, but tolerable. I'm debating keeping it turned on for good. I like being able to clearly see what's on top of what, and you know what? Drop shadows are just sexy.
To turn the shadows on in Kubuntu after install:
For an ATI card (nvidia's are slightly different)
* Add these lines to your device section:
Option "AllowGLXWithComposite" "true"
Option "backingstore" "true"
* Add this extension section:
Option "Composite" "Enable"
* Right click on any titlebar and choose "Change window behavior"
* Set your translucency and shadow options.
* You could just restart X, but I didn't see the change actually happen till a full reboot, since I'm using KDM and killing X just seemed to drop down to KDM.