I have to say that I think his best years are sadly behind him.
He was on a winning streak from Dark Star up to Big Trouble in Little China, but after that his output became more variable.
I know he had difficulties working with the big studios, but despite this I think Starman and Big Trouble are among his best works.
He did find something of a return to form with Prince of Darkness and They Live, concerted efforts to going back to making smaller, low-budget horror/sci fi movies.
But then he also came up with real stinkers like Memoirs of an Invisible Man...what was he thinking? Chevy Chase...? And the tone of the movie was all over the place...part conspiracy thriller, part sci fi, part comedy.
In the Mouth Of Madness was ok - I particularly remember going to a screening of it at the NFT in London before it was released, with Carpenter in attendance giving a Q and A. I remember vividly that when the movie finished there was muted applause, and when he came to take questions, you could see he felt very uncomfortable. And afterwarRAB when I left, I saw him sitting completely alone at a table, waiting to sign autographs for people...and no one around. Very sad.
Then came pointless remakes and sequels (Escape from LA, Village of the Damned), and expremely forgettable fare such as Vampires and Ghosts of Mars...then a lot of downtime and a few tv anthology episodes.
And then there the 'ones that got away'. Projects he wrote or initiated, but did not get to direct them, such as Halloween 3, Black Moon Rising (dreadful movie, but had the germ of a good idea and in Carpenters hand's could have been something else), and Eyes of Laura Mars.
But...let's remember that he did make some of the most iconic movies of the 70's and 80's, and he appears to have a couple of interesting films in production at the moment...so let's wait and see.