Version: (using KDE 4.3.3) "Low Disk Space" window has no icon. Screenshot attached.
Created attachment 38519 [details] Screenshot
This is an OpenSuse addition, but it may be introduced into KDE...
Ah, but let's not queue bug reports for possible future additions here. The freespacenotifier in playground does not use the dialog presented in the screen shot, but a KNotification. As such, this bug is probably invalid once it moves to KDE. If you want that fixed for the version you are using, file a bug report at http://bugzilla.novell.com/