number one by far has to be TRON. I've watched that movie a few times over mostly because of the soundtrack (and how well it fits with the movie).
LOST's got some great tunes too.
Seriously. Hearing this right now makes me want to go watch it. SO GOOD.
I'm trying to figure out which LOST song to post... I'm having a really hard time haha. "Life and Death", "Parallelocam", "Flew the Coop", "Ultrasonic Flash", Jumping Jack's Flash", "Happily Ever After" and "Moving On" are beyond incredible. Aaaaaaaall of them.
I think the soundtrack for City of Angels was better than the movie. You can't separate Top Gun from the soundtrack. I love that Grease was mentioned. I also love Grease 2. (I know I am probably the only one.)
It may sound lame, but the first couple of seasons of Grey's Anatomy, they really linked the show and the music together. The CD's they released I still really love.
Philip Glass for The Hours, Illan Eshkeri for Stardust, Hans Zimmer for Lion King...aaand I can't think of any others right now. Obviously Klaus Badelt for a few of the films he's scored but nothing phenomenal in my mind. I love Patrick Doyle for Great Expectations and A Little Princess, too.
I'm too lazy to post clips, but my favorite soundtrack of all time is probably Edward Scissorhands - very haunting. Actually, most of Danny Elfman's scores are quite nice. I also love Hook (soundtrack is better than the movie actually!), Lord of the Rings, Jurassic Park, Sunshine and Gladiator.
Oh, and the end music from Field of Dreams makes me tear up, even when not watching the movie!