I like soundtracks from older movies (60s-70s).  Henry Mancini's music from the 
Pink Panther movie series is classic; but my favorite movie soundtrack music from that era was the jazz-funk-rock of Lalo Schifrin, who scored the 
Dirty Harry series, 
Enter the Dragon, 
Bullitt, and many more.
James Horner did a pretty good job of aping Schifrin's style in the soundtrack for the early-80s Eddie Murphy vehicle 
48 Hrs.
Other jazz and soul artists did some great movie scores too.  Herbie Hancock's work on 
Blow-Up was a good example.  His "Bring Down The Birds" from that movie was the main sample used on Deee-Lite's "Groove Is In The Heart" from the early 90s.  I also really enjoy Willie Hutch's soundtrack to the 70s blaxploitation film 
The Mack - not as well-known as Curtis Mayfield's contributions to 
Superfly or Isaac Hayes's work on 
Shaft (also both fantastic), but it holds its own.
Along the same lines: old TV theme music from the 1970s.  I'd love to hear a jazz group do an extended jam on the theme to 
Barney Miller, for example.
A cool niche genre of music is "soundtrack music for movies that don't exist."  Two examples:
The James Taylor Quartet, a British group led by the eponymous Hammond organ player (not to be confused with the American singer-songwriter known for "Sweet Baby James"), has covered a lot of older tunes from TV and movies, like the themes from 
Starsky and Hutch, 
Goldfinger and 
Mission Impossible.  They released an album of original spy-movie soundtrack music called 
The Money Spy-der in 1996.
There's a group called Federale, which shares a couple of members with the Brian Jonestown Massacre, that specializes in original spaghetti-Western soundtrack music for nonexistent movies.  I saw them open for BJM once; it was really cool seeing that kind of music performed live.