I'm looking for an equivalent of Ctrl+Alt+Del on Windows for OS X.
Note: I am not looking for cmd+option+esc and this is not a duplicate of any questions asking for a "task manager".
Ctrl+Alt+Del on Windows uses an interrupt whereas cmd+option+esc is just another keyboard shortcut. If the system is stuck (hung, etc.) cmd+option+esc will not respond because it's just another user-mode program/dialog like any other.
I'm looking for an interrupt-based solution that will allow me to take control of an unresponsive system. OS X is (by and large) more stable than Windows, but when it gets stuck I have not found a solution as powerful as Ctrl+Alt+Del on Windows.

ctrl+alt+delnot work on Windows machines as well, in cases where I thought it should. – Hawken May 6 '12 at 3:39