Is there is any point in just listing things, without being able to discuss them?
Anyway, since posters don't make the rules here, I'm going to say Dustystreet and RT - Apocalypse Now, Citizen Kane and Bladerunner - WTF? That's all! A agree with you about the Thomas books though - the originals are beautiful and evocative and I have them all still.
Anyway, my choices - which are open season for discussion...
On films, the Lord of the Rings films must be the most overhyped overrated films ever. The books were pretentious enough (although of course I loved them as a kid) and then were given this awesomely hyberbolic over-emoted, unsubtle treatment where everything was just SO EPIC!!!! (and I mean the capitals etc.). But then most recent films are overrated and overpromoted... and since this one is the 2nd best film of the new millenium according to IMDB voters, it is definitely overrated.
Of supposedly quality films... I just have to pick The Shawshank Redemption simply because it is the popular choice for 'best film ever' and it quite clearly isn't by any stretch of the imagination. It's not bad, indeed it is a better than average film that tugs at the heartstrings certainly, but there are several hundred better films that are superior in all kinds of ways, including the three voted for by previous posters, so it gets my vote as most overrated just for that reason.
Music. Rush. Or is that just the worst? I don't know. But I run in sheer terror and in fear for my eardrums when I hear them. And yet so many people (especially men of a certain age) seem not only to be able to tolerate them, but to actively love them. And U2. Best before sometime in the 1990s. And Bono is not the messiah, and he's no longer even a naughty boy, he's just an irritating combination of earnestness, stupidity, ego and the writer of the worst lyrics ever (e.g. "a mole, digging in a hole, digging up my soul" gotta think of somehing else with 'ole'... awful).
Don't watch TV...