I'm a huge fan of John Carpenter's movies and I hate to imagine most of his stuff without the opening credits. The mood for Halloween is set infinitely better by having the theme playing over the jack-o-lantern & the credits than if the movie had just started with the opening tracking shot.
Today, if you see a movie that isn't from a major studio, you get logos from 3 or 4 companies that put up money and then they follow it up by immediately listing the company names again before the title of the movie. :D
I was thinking the same thing about credits more often being at the end of the movie just the other day. I can understand that in some cases, a movie gets down to business so they don't want to have the credits over top of the movie but many of them could have the credits play over the opening...