Of course, there are too many cool ones to name in one post, so here are a today's notables.
Several more screenshots at my Flickr account.
The Curious Case of Benjamin Button: Indian, Triumph
THX1138: I'm glad to see that in the future police droids are riding custom Triumphs with Avon fairings:
Indiana Jones and the Kingdom of the Crystal Skull, Harley, Triumph
The Wild One, Brando's own Triumph