I am another happy TapTap user.
I use it to launch Launchy with Ctrl Ctrl. Seems to make some logical sense because it is next to the Win key, which in Vista/Windows 7 does kind of a weak version of a Launchy/FARR thing with the Start menu if you press the Win key.
I have it send an Alt-F13 (a key I can't press accidentally and which is unlikely to be a conflicting hotkey with any application, UNLIKE Alt-Space which is the Launchy default), and I have Launchy hotkey configured Alt-F13.