Did you ever figure out a solution for this? I'm now having the exact same problem on a 3-year-old MacBook.
The problem, to restate: the iPhone charges when plugged into the wall, charges/syncs when plugged into any other Mac, but will not charge, sync, or be recognized at all by this particular MacBook. The USB ports work fine for other USB devices. Trashing the plist, resetting pram, etc., do nothing.