First off, just wanted to say that the Beatles are not overrated one bit. Any credit they get, they deserve and then some. I could probably name 50 Beatles tunes off the top of my head that are fantasic, catchy tunes that I could sing from start to finish from memory. FIFTY!!!!!! Some bands spend their whole career just to get that one song that gains some decent status on the charts. The Beatles were SO innovative, SO unique, and probably the best pop song writers of all time. There's more derived from the Beatles than meets the eye in terms of music these days. Why do you think Portnoy and Paul Gilbert played the Yellow Matter Custard show and revere them so much. Everything from Symphony X to Type O to Racer X to Dream Theater has Beatles written ALL over it. But that's it for the Beatles rant....
Here's where I really get into trouble
....
I think Joe Satriani is obsurdly overrated, probably the single most overrated guitarist and composer. All his themes and songs fall apart into a sloppy jammy mess that is mostly just tricks, slides, and harmonic bends and no real taste.
Blind Guardian is great, but they get way more credit than they deserve considering the amount of really boring material on all their albums and the fact that they don't have one single good, tastefull solo.
For classic rock biggies, Zepplin is overrated, especially Jimmy 'sloppy' Paige, but at least they were innovative. The Rolling Stones, however, are just completely overrated in every aspect available.
Metallica is overrated, duh, Kirk Hammet needs to be forcefully told not to play.... EVER AGAIN!
Here's a REALLY harsh one...I think Cacophony is overatted in the metal/shred community. They have some stuff that is just mindbogglingly good, but they couldn't write a catchy riff to save their lives, and their singer was hands down the least talented human on the face of the planet. Their shred was about 50% fantasic and 50% filler I could really have done without, nothing in between.
Conversly, who doesn't get nearly enough credit:
Brian May from Queen
Type O Negative
Gamma Ray (I won't even start, but what a joy it is to listen to those guys)
Jordan Rudess (everyone looks at Dream Theater and sees Petrucci and Portnoy, but the REAL prodigy there is Jordan. He's amazing. GET FEEDING THE WHEEL)
Alright, that's my rant, don't go getting too up in arms over it if ya disagree now