This is going to be short (PS3 buffer!). I have fairly varied tastes in movies, bit there are a few (probably had to buy them from the US) older movies that I particular like for some obscure reason.
These "gems" include "Dark Star" (the only 70's one) a John Carpenter movie. "The Adventures of Buckaroo Banzai Across the 8th Dimension" (count the stars!), "Night of the Comet", "Killer Klowns From Outer Space" (just plain bizarre), "Spacehunter: Adventures in the Forbidden Zone", "The Ice Pirates" (it was a comedy Sci Fi movie and had its moments) and a possibly more mainstream movie "Big Trouble in Little China".
I am surprise to find Peter (Robocop" Weller, Chrstopher (Back to the Future) Lloyd, John Lithgow (currently in Dexter) and Jeff (Jurassic Park) Goldblum appearing in Buckaroo Banzai. Ellen Barkin is also a "bigger name" from the past and in that movie.
I suppose the appeal is that the movies are differnent from your normal mainstream movie. Most seem to be available in the UK... now!