I guess when I think about the past it's either neutral, or it's negative. I get a lot of "would've-could've-should'ves" going on and I end up getting frustrated about things I should've done earlier or some such. Every once in a while I'll dredge up a positive memory, and I feel guilty that I don't think enough about the positive things in the past. In fact, I discovered (through therapy, go figure) that sometimes I need to revisit the past, in order to heal something broken. If I don't "fix" it now, I won't be able to go forward.
But as far as movies are concerned, I have a collection of favorites. Movies and good tv shows are ways I de-stress - and I'll often revist old shows or movies if I need to feel good about something. Or I'll turn on the TV (i.e., internet) to find something worth my time so I can feel "better."