I can confirm this problem using Edgy (64bit, gnome) and nvidia-glx. I can also confirm that disabling the the work-around suggested by jamespharaoh (disabling the composite extension) does work.
I'm going to see if I can get the latest nvidia-glx drivers installed manually - if that solves the problem (without disabling the composite extension), I will report it here. ** Attachment added: "An xorg.conf with Xinerama enabled and the composite extension disabled - it works too!" http://librarian.launchpad.net/5084350/xorg.conf -- gnome-terminal does not start when using xinerama and nvidia https://launchpad.net/bugs/58232 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs