An AppleInsider post earlier in the year had indicated that Apple would be showing something "super secret" at tomorrow's Final Cut Pro user group meeting. The most likely scenario at this point is that the secret technology is in fact the MacBook Air that was announced today. A product to replace Shake (code-named Phenomenon) has been rumored to arrive in 2008, but it is doubtful that that product's introduction would take place in such a setting.
We have also heard unconfirmed rumblings that MacBook Pro updates are to come shortly, though no exact timing is indicated.