The most epic croissants I've ever had were, naturally, in Paris.
Our group had a small hotel near the Gare Saint Lazare, and next to the hotel was a bakery.
They had a croissant with an incredibly sharp cheese and the best cured ham I've ever had anywhere, and it was cheap, something like $1.30 or so.
The croissants themselves were unlike anything I had ever had before, or have had since. It was like biting into a down pillow that had both structure and which melted in your mouth at the same time. Most of the croissants I've had since have been either heavy and leaden, tough, or have just shattered.
I'd love to try my hand at making them, but its INCREDIBLY hard work if you don't have a sheeter to do the rolling for you.