of the ones mentioned, i have to favor:
Back to the Future - just the 1st one.
Somewhere In Time - beautiful, romantic story and music. and Christopher Reeve!
The Butterfly Effect - surprisingly awesome, despite Ashton.
another great one i recently rented and was delighted by, is The Lake House. starring Keanu Reeves and Sandra Bullock. loved it.
and, just yesterday, i finally watched an old 80's movie called Flight of the Navigator. it wasn't great, but it was kindof interesting. and there was a little bit of a time-travel aspect to it.