I'm glad I'm sticking with it, cause Quicksilver and a MacBook Pro would appear to be a match made in heaven. As promised, QS is starting to adapt to my most-frequently-pecked sequences, and making the delay between impulse and execution lighting-quick. Ctrl-Space + 'f' launches firefox in about the time it takes to think about it. So, QS is still basically an application launcher for me, but it's a good app launcher.
It's probably time, though, to graduate on up to some more advanced use-cases, so I'll spend some after-hours time in the coming week exploring the Quicksilver category on 43folders. (Where I've already noticed this this excellent introductory vid-cast from Merlin and the lads at MacBreak.)