On behalf of Linux users who use this to open Terminal... NOOO! I use this key combo constantly and it would take ages to unlearn it. Ctrl+Alt+T = open a terminal window, dozens of times a day every day.
What if the new tab had a command line inside of it? That would be perfect!
You're an emacs user, aren't you?
Firefox actually has a command line [0], though it's not a terminal. I'm pretty sure there's an extension for a real terminal, though.