Favourite Start To A Movie

[sskink]

Two that come to mind that always give me a smile:

Kevin Smith's apology to porpoises in Dogma.

The beginning of Waking Ned Devine, between Ian Bannen tricking his wife into bringing his apple tart sequeing into the motorcycle on the Irish countryside to the tune of Fisherman's Blues.

[Cida]

If by "start," you mean the first shot, the two that immediately come to mind are Touch of Evil and Raiders of the Lost Ark.

If you mean opening scenes, then there would be a lot more, like maybe The Thin Man, toward the beginning when Nora enters.