In Feisty I have the same problem with Nvidia/Xinerama/AMD64. The workaround posted above (Option "AddARGBGLXVisuals" "True") works around the problem and gnome-terminal will start OK again.
-- 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