EDIT: When I uploaded the "Debian MoreBlue" files, I was not aware that they are provided by Debian's "desktop-base" package.
I found this beautiful theme in one of the early KDM packages for Debian Lenny. For reasons unknown, it seems to have been dropped in favor of the "Circles" theme.
This theme is particularly great when matched with Splashy's "Debian MoreBlue" theme, so that from boot to login, you have one consistent theme.
For further consistency, set the enclosed "kdm-bg-debian-moreblue.png" file as the KDM background (which you can set from KControl >> Login Manager >> Background tab or by editing the "Wallpaper[$e]" line of the /etc/kde3/kdm/backgroundrc file).
Then you'll have the same theme running from boot through login and all the way up until your desktop appears.
Here's a link to the "Debian MoreBlue" KDE3 Splash Screen:
Here's a link to the "Debian MoreBlue" Wallpaper: