Lots of the good ones have already been mentioned, but here are some more.
Simple but perfect:
http://www.youtube.com/watch?v=V4kWpi2HnPU
From the Escape From L.A. soundtrack (horrible movie but some good songs):
http://www.youtube.com/watch?v=53qeiAVjHQU
I tear up every time I hear this:
http://www.youtube.com/watch?v=ypoUBGMxT1o
Underrated and forgotten: Dune, Legend
Overall best soundtrack ever, though...The Karate Kid. Both the orchestra and songs always fit and enhance the mood perfectly. After 30 years and dozens of viewings, it still feels fresh and alive.