Hello, I was having the same problem with KDM taking about a minute or more to start. Then I found this: http://www.linuxformat.co.uk/modules.php?op=modload&name=phpBB_14&file=index&action=viewtopic&topic=5678&forum=1&5
Basically the solution is to 'dpkg-reconfigure fontconfig' to rebuild the font cache. It might be possible to just do 'fc-cache -f -v' (from the postinst for fontconfig) but I didn't try this. Now KDM starts in a few seconds. Cheers and such, --Barry