I dunno. I'd still go with the Beatles and Velvet Underground being overrated. By some at least. There is a limit to the amount of hyperbole that can be thrown upon a pop group. Even very good pop groups and very creative ones. This has little to do with the fact that along with Sonic Youth, this rounds out my list of three favorite white performing groups.
Underrated is more interesting. Bo Diddley is underrated. There would be no garage rock without Bo. Nor half of classic rock for that matter. No Velvet Underground (also see the bridge from "Peggy Sue") and no Stooges. No punk. No 80s. Of course, I'm exaggerating a bit. Like Beatles fans do. This stuff would have found a way to be invented. Maybe later and by different people. There's more of a point to Beatles and Dylan hyperbole in that, Rock and Roll really could have been a passing fad, and without some pioneering attention being drawn back to the medium, soul music (say) could have dominated the 60s -- more than it did, if you look at the charts, rock was really only one piece of the 60s. Once the collective creative energy of the entire collegiate english speaking world was being applied to rock and roll, I don't think there were many innovations that wouldn't have happened naturally. The world did not hinge on the Beatles' every single activity. But in 1963 - 1966 a lot of people heard the Beatles and Dylan said "OK, my friends and I need to do this." Most things since then have been occasionally amazing, but not essential in the same degree.
I guess there's two spirits of "overrated." 1) In my judgement, a popular opinion is a bit off. and 2) GOD! It's so irritating that everyone likes this! Listen to what I like!
Like "ironic" and a lot of slang. It's a word that begins to say more about some group of people who use it than the intended definition of the word itself.
Tarantino is to filmmaking what Prince Paul and the Dust Brothers were to music production. Which is to say, not nearly everything, but certainly a lot, especially if you're considering modern film in and of itself, and not directly against 100 years of history. Tarantino is a lot more overrated if you're pitting him against Welles et. al. than if you aren't.
So yeah, I'm one of those people who may know way too much about this kind of stuff. But I don't believe that any aspect of taste is objective, not even harmony vs. disharmony (listen to field recordings of pre-agrarian societies - it's a real mixed bag), but rather a slow invention by society at large. I can't imagine anyone not liking Duke Ellington (over 5 decades of recording and more of performing and he did almost no wrongs) but what we can't imagine in other people is more an indicator of our social conditioning than what is and is not possible or even legitimate.