I suppose there's so many reasons a particular aircraft stick out against its contemporaries, fairly or unfairly depending on your point of view.
Some aircraft became 'dead ends' in development, some reached the peak of their ability rather quickly (and nevertheless performed well and for a long time), or perhaps were obsolete before they even reached operational duties (such as the Whitley).
Some of course were derived from hugely popular, romantic and prestigious racing aircraft, like the world beating Supermarines that ultimately inspired the Spitfire. That whole era was probably rooted into people psyche, and perhaps carried on into the future to us.
Thats not to say anyone who flew in other aircraft deserve any less regard, of course not...
But look at some of the facts...
Spitfire, developed from something so popular and well known, uprated throughout its entire operational life, continually faster, more powerful, developed into many roles from ground attack to sea duties (which co-incidentally, the Hurricane did as well), developed in the early 30s, (about the same time as the Hurricane) built well into the late 40s and operational into the 1950s. An immensly capable aircraft, the important fact was it was perhaps overengineered in the first place, allowing it to adapt and be uprated long into its life. I remember reading someone remarked early in its life how 'deep the wing cord was' (whatever that means), but it appeared to be a critical design neccessity for its future development. Whether they saw the implications of that at the time or not, it doesnt explain. I guess the fact it was mentioned inferred it was critical.
There were so many subsequent variants , that simply indicates its ability and popularity. And of course...its stunningly beautiful.
The Lancaster was such a huge leap compared to its contemporaries, and again had the features that allowed it to be uprated and evolve long into the future, to become the Avro Lincoln and eventually the Shackleton (which i can remember seeing in an operational role regularly when i was a kid.)
They had long distinguished lives, they were there to be seen for so much longer than others, perhaps thats partly why they are rooted in peoples minds.
All that said, every aircraft, whatever its make, was special to its crew. Dad was an aviation artist who did a lot of commision work for ex servicemen who wanted to see the aircraft they flew on canvas, he did everything from Lancasters to Spitfires, from Avro Ansons to EE Lightnings, from Chipmunk trainers to the cumbersome and ugly Blackburn Beverleys, every concievable make.
He always said, every one of them is special to the people that flew them...and i guess, every person that flew in them was special too....but inevitably, some aircraft just stick in peoples psyche.