The KDE logout window shows 
Konqi, a cartoon of a dragon that is cute about twice and then gets annoying. If you want to get rid of it, find a PNG file called shutdownkonq.png on your system and overwrite it with anything you like (preferrably an image with a transparent background). The exact location varies on different systems:
Another option may be to define a user-specific version of this file. The command “kde-config --path data” shows the sequence of directories that KDE components use to find their data. For instance, on Gentoo, it lists the following directories:
/home/username/.kde/share/apps/:/usr/share/apps/:/usr/kde/version/share/apps/
Presumably this means that a file named ~/.kde/share/apps/ksmserver/pics/shutdownkonq.png will override any systemwide file with that name.
If that doesn’t help, locate(1) should help you hunt down the file.
By default, KDE will open links using Konqueror. There's nothing in the GUI configuration that will let you change this. Neither the FAQs on kde.org nor the MailingList archives contain any hints. A Google search turns up a lot of people asking but very few functional replies. The common suggestion of changing the association for the text/html MIME type only changes the how HTML documents on your HardDisk are opened.
The general way is to have ~/.kde/share/config/kfmclientrc read as follows:
[Settings] ExternalBrowser=/path/to/browser
On Debian, however, you should simply set the BROWSER EnvironmentVariable to the path to the WebBrowser you want.
See FontNotes.
Start the Control Center and bring up KDE Components → File Accociations. In here you can add/remove and edit default file associations and the open with menu. If you can't find a file association, it is probally hidden under the Applications area.
Using KNetwork Manager 0.2 (KDE 3.5.8) to configure a manual network connection will write to /etc/network/interfaces. This will subsequently prevent the automatic detection of and connection to wireless networks other than the one manually configured. The only way to regain this ability of detecting and connecting to wireless networks is to edit the /etc/network/interfaces file and remove all entries except the loopback entry and restart the networking daemon sudo /etc/init.d/networking restart
