Since OpenSuSE 10.1 alpha 4 the K desktop manager (KDM) clears the environment variables for new sessions. It's regardless, which session the user starts with KDM (for instance kde, twm, ...). 

The only exception is the session "failsafe". In failsafe the environment is not cleared.

I think, clearing the environment variables is a bug, because users expect, that they can set environment variables with /etc/profile.local and $HOME/.profile scripts.

The PATH-settings from /etc/profile and /etc/profile.d/*.sh are also cleared by KDM. This is the minimal PATH after starting a KDE session:

$ echo $PATH
/opt/kde3/bin:/usr/local/bin:/usr/bin:/bin:/usr/X11R6/bin:/usr/games

I don't know, if KDM itself clears the environment. It's also possible that a X startup script clears the environment or the profile files are never read.