You Only Live Twice
Good film, and would (and should) have been a fitting enough send-off for Connery as Bond, but I feel Donald Pleasence is completely wasted as Blofeld. He's in it for what seems like less than ten minutes (and he's only properly on-screen for around five), during which time he hams up a few lines and then legs it... only to be replaced by two other arguably inferior actors in the next two movies.
Shame.