It might seem obvious and allure but if a score is done well it can lift an entire movie. Now, if the score is beyond the normal level and is an adding element to an already good story and actors we're talking about something special. Some composers have made lots of $$ and it's not until you've glanced behind the scenes you really understand what it means to create timeless scores. Let me share my favorites...

This might not come as a surprise but Contact's score tops everything I've ever heard. The movie is in itself a perfect symbios of everything I find interesting/entertaining and the score sure is a big addition. It's timeless yet so simple.
Gladiator's score made by Hans Zimmer is also what you would like to call timeless. Let's not forget Lord of the Ring which isn't a favorite movie for me but I love the score 'Breaking of the Fellowship' which is everything you can ask for. Other great scores includes movies such as Braveheart, Terminator, Star Wars and Brotherhood of the Wolf.
To sum it all up I won't forget the many classic TV series/shows through the years; how can you forget Dallas, Falcon Crest, McGuyver, Snoopy, Chicago Hope or The X-Files just to mention a few.

Music compostions are so essential movies wouldn't be anything without them.