One movie that's the best I've ever seen so far in my life? Easy.

'The Mummy' (1999) with Brendan Fraser, Rachel Weisz, John Hannah and Arnold Vosloo. All great actors which made for a outstanding movie (made on a very low budget as well!!)

harry potter

Children of Heaven.

There is not just one, but if I had to choose, it would be:

The Good, The Bad and The Ugly
http://www.imdb.com/title/tt0060196/

Black Hawk Down