Everything else past STS-1 actually was nothing special anymore but still exciting.
I am going to add something here.
I agree with what you are saying, STS-1 was something special. First time the Space Transportation System ever flew, and it flew with two people on it. So many questions on that flight. Will the tiles hold, the SRBs, if things go wrong, do you really want to use those ejector seats and jump out of the thing. The payload bay doors, will they open and how easy will it be to get them to close again. They flew that thing, and they flew about as perfect as you could have ever hoped for. That landing on STS-1 is still one of the best you will ever see of a shuttle coming home.
But there were some amazing things to follow in the STS program. Mainly the EVAs. The Shuttle era saw the orbital EVA go from going outside and doing small tasks, to spending several hours at a time repairing satillites, building a space station, just amazing stuff. And Bruce McChandless on STS-41B, taking an MMU some 300 plus feet away from the Shuttle, with nothing attaching him to the orbiter. That is still something that give me chills thinking about.
Something could be said for STS-2 being amazing, in that Engle and Truly were the first people to go into space in a USED space craft. The first test to show that Columbia was in fact re-usable.
But STS-1 does stand out from all the rest for me. Apollo 11 of course is close behind, but thinking about it, Apollo 8 had already went to the moon, Apollo 9 already tested the LM, and Apollo 10 did pretty much everything except land on the moon. STS-1, there was nothing before it, the whole mission done for the first time with two men aboard. And they flew it perfectly.
My vote goes for John Young. The first to fly Gemini, flew to the Moon twice, showed how to really drive the lunar rover, and flew the Shuttle twice. Then went on to work for NASA for some 20 more years.
And he saved Columbia from being destroyed on STS-9, when two of the GPC's crashed. If he let the BFS take over the de-orbit, loss of vehicle and crew. The pefect example of an Astronaut.