I've long had a theory that any great movie/TV show will have at a MINIMUM a great opening theme song, if not a great BGM.
The Dirty Pair Movie (AKA Project Eden) - I consider it one of the great crimes in video that this movie was released in mono.
Dirty Pair TV series
Dirty Pair "The Conspiracy of Flight 005"
Project Ako - Music was produced by the guys who did the music for Flashdance
Dominion- Tank Police : Tankyboy's Light Your Fires!
Bubblegum Crisis OVAs (Original)- The music was by far the best thing in this OVA series.
Kimagure Orange Road - I have a boxed set of something like 10 CDs from this 48 episode series, some redundancy, but still.
Star Wars/Empire/Return - Is there a greater piece of music than the Imperial March?
Cowboy Beebop - Hey, the series was half named after a musical style.
Char's Counter Attack - Some very good orchestral works in here
Akira
Area 88 (the 80's OVA series)
Twin Peaks
Big Trouble in Little China