Dade uses the Powerbook to "hack the Gibson" at the end of the film.
Year of feature (shown above)
dade's computer before this one (the one he spraypaints with camouflage pattern) is an outbound portable
I've seen a number of suggestions that the Outbound might appear in this film. I don't think it does, though. Dade's machine has a rather bizarrely placed trackball next to the screen that doesn't exist on the Outbound. I think it's probably just a mock-up. I'd love to be proved wrong, though!
Dade's laptop that he spray-painted camouflage is actually a <a href='http://en.wikipedia.org/wiki/Macintosh_Portable' target='_blank'>Macintosh Portable</a> from 1989 - 1991.
A number of people suggest that Dade's machine is a Macbook, but I just don't see it. It's a completely different form factor - again I draw your attention to the trackball being next to the screen rather than next to the keyboard.
not to get too pedantic, but do we know for a fact that this is not a 520c?