My machine is taking ages to get from the login screen after booting to actually showing the gnome desktop (as in, over a minute). It seems as though it is just waiting for a long period of that time . This has been a problem for a long time. The bootchart is available - any ideas on what is causing this? (Also on superuser)
Have you tried creating/logging in with a diffent user account?
Perhaps you could try to delete all the ~/.gnome* files and folders in order to be re-created from scratch.
You will lose of course all of your personal settings, but i think it deserves a chance..