I cannot see, if lxdm login manager is in the backports (?). As for me,
i had to get it from the ascii repositories.

With this login manager i solved the exit/logout problems i had with
slim *AND* lightdm (light is an euphemism!). And by the way i saw,lxdm
isn't somuch heavvier than slim. May be it is a good option (at least
for me it is). So it would be nice to have it available by default even
in stable.