I've been lucky enough to have quite a few "interesting" passengering experiences (many of them thanks to HMFC, in one way or another):
- jumpseat on Tristar for night departure from Ascension Island
- seeing large amounts of the SW of England from the cockpit of a Herc at 250 feet, 250 Kts
- seeing most of the Falkland Islands (some from very low altitude indeed!) from the back of a Chinook
- looking at Cypriot beaches out of the open side door of a Wessex
- a short, but unforgettable ride around Gloucestershire in a big comfy swivelling chair, in a Gulfstream 5
- getting a rather tatty hired 172 from Larnaca to Beirut and back again (1996, when Beirut wasn't looking it's best).
- over the Grand Canyon in right-hand seat of a PA31
- Squirrel heli over the rainforest, beaches and mountains of St Lucia
- Squirrel heli over Sydney Harbour at dusk
As far as when I've been flying myself:
- First solo, QXC (went perfectly), first Cross-Channel, first flight taking family & friends etc
- "Bay Tour" of San Fransisco at 2000 ft in rented 172. Over the Golden Gate, Alcatraz and then the 4 runways of KSFO with the heavies arriving and departing all around us....wish we could do that at Heathrow!