Breaking out to the terminal

Every so often my laptop locks up with some rogue process taking up all the i/o or processor. I then spend ages fighting with the mouse to open up the Applications menu so I can open a terminal so I can diagnose the problem and kill the process.

Is there a quicker way to break into the terminal?

CTRL+ALT+F1 should give you a terminal where yon can log in to diagnose the problem. You can press CTRL+ALT+F7 (sometimes F8) to return to the GUI.

There are additional terminals in CTRL+ALT+F2, F3, etc...

I also find very useful to map CTRL+ESC to the system monitor, where I can kill a process quickly.

As SW01 said, you can also type ALT+F2 to execute one command. This will only work if gnome-panel is enabled (it works by default).

And fred.bear added than CTRL+ALT+T will open a new window with the default terminal.

The default keymapping for the default X terminal is Ctrl+Alt+T

Javier's answer is imo the best, but I figured more info is never a bad thing.
You can also type alt+f2 to open a small prompt. From there you can open bash or some other desired program.

If your system is utterly unresponsive, you can press Alt+SysRq+K (the sysrq key should be the same as the Print key) to Kill the X display server and all its child processes.

This will throw you back to the GDM login screen, killing all applications currently running on TTY7, which is the one where X is running.

→ More information on Magic SysRq Keys at Wikipedia.

Of course you will lose all unsaved data, and you won't know what process went awry, but it will respond even if some process prohibits you from doing everything else, the magic sysqr keys have highest priority.

If your system is still responsive enough to do what Javier Rivera suggested, this is obviously preferable. Type in ps aux on the command prompt you'll get through Ctrl+Alt+F1 to get a dump of all the processes currently running. You can use Shift+Page Up to scroll though lengthy output.

guake

can be opened with F12 and does a very good job even if your system is overloaded! It's a quake-style terminal.