This is a hard one:
Teddy Boston's Olton Priors- 60's scenery and lots of proprietary hacks, but it was a real railway, it worked to a timetable and it felt like a real place.
Garsdale Road - the layout was probably better it photos than reality but it looked like the real thing, was believable and led to the Long Drag.
WS Norris' O gauge layout. - I don't care that he had loads of money and access to tiger whiskers it was simply stunning and years ahead of the rest.
(Guess who grew uo with Dad'sRailway Modeller and MRN collection.)
loads more inspiring layouts but only allowed 3 and I'm so surprised that none of these have been mentioned yet.
Kev