In my opinion, the problem with any "which bands are overrated?" thread is that it's so easy to say all these famous bands are overrated, provided you don't have to say who was actually superior to them. So you get people who say, in effect, "well in the 60s and 70s, the way overrated bands were the Beatles, Stones, the Who, the Doors, Pink Floyd..." Basically, you're saying that the mainstream, Rolling Stone magazine-endorsed opinion of who were the greatest rock bands is completely wrong. But who's going to take their place? So like, if the Beatles were so terrible, who are all these bands that were actually way better than the Beatles?
I suggest that for each band you say is over-rated, you should be required to go out on a limb and name a somewhat comparable band that was better.
Overrated: The Eagles. Underrated: CCR
Overrated: Red Hot Chili Peppers. Underrated: Faith No More.
Overrated: Pearl Jam. Underrated: Dinosaur Jr.
Overrated: Metallica. Underrated: Meshuggah.
Overrated: Eric Clapton. Underrated: Jeff Beck.