In that cheesy 80's film Electric Dreams when uber-geek Miles Harding (the protagonist) goes to buy a computer at the start of the film (well first 30 mins) he goes into a computer shop, and if you look really carefully there is a boxed Commodore 64 on a display to his left. You have to look really quick though :-D
I am also pretty certain that there is a Commodore in the film War Games (with Mathew Broderick), but I can't remember whereabouts... I'll have to watch it again, and check... it's a pretty good film actually, so not that much of a chore to watch. :-)