I liked some fighting game intro's, in particular Capcom vs SNK and Garou: MOTW.
for the really retro-stuff: Salamander on MSX. A genuine intro-demo, and the logo exploding onto the screen - all this on Z80-based hardware in 1988
I also liked Strangleholds very short but very stylish intro. Unfortunately this intro was a too good illustration of what the game itself is like... stylish indeed, and very, very short.
(story wise it also did too good a job at emulating hong kong cinema, because it's as crappy as those old Woo movies (before he went to hollywood))