Hi. I was trying to use step by step this wiki guide http://wiki.debian.org/ATIProprietary and no problem appeared.
But after reboot my machine, I got a just terminal with login. So I ran startx and got twm.
my xorg.conf has same lines like wiki tut. I tried reinstall gnome with apt-get install --reinstall xserver-xorg but no change.

Could you please give me some hints where to start to solve this issue?
Im new to this stuff.

/edit: so, dont know what eaxactly happend but I 'solved' it with: apt-get install gnome, apt-get install gdm, dpkg-reconfigure xserver-xorg