Of course all of John Williams stuff is my list, his work with Harry Potter is getting progressively better with each movie IMO, Something Wicked this Way Comes and Hedwig's Theme from POA are two brilliant masterpieces.
Zimmer's haunting, brooding score on both Batman Begins and his swashbuckling "trailer-music" Pirates of the Caribbean are also great pieces of work(even though POTC is a little off balance with greatness one minute and blandness the next)
What about you guys?