Concorde for me. Toured the one on static display at MAN, but the cabin is really nothing to write home about. Still wish I had been able to cross the Atlantic on one.
Shared second place goes to the Tu-154 and the Il-62. With cold war making its surprise comeback, I guess I can bury that dream.
Honorable mention, though it wasn't an airliner: the An-225. RIP Mriya.
The ones I got crossed off the list: the MD-11, to SXM and back no less.
The Super Constellation, at a local aviation festival a couple of years ago.
And the 727... well, I've never flown on one, but the one Vic, Jeff (SFO) and me were allowed to inspect on a memorable day at OPF came close enough.
Ideology: The mistaken belief that your beliefs are neither beliefs nor mistaken.