Top of the list, of course, is Concorde.
Then the IL
-62. I toured one on static display at an air show, but have never gotten to fly in it.
Also the Caravelle. I wish I could have flown on one of those.
I have flown on the VC
-10, which several of you mentioned wanting to fly on. I totally loved it...great airplane!!
I feel lucky also to have taken quite a few flights on the BAC-111. Tremendous kick on takeoff!!!
Those who want to do something will find a way; those who don't will find an excuse.