Greatest Band? Whos yours?
 

The misfits

Even though I'm not a huge fan, I think Dream Theater is the obvious choice. I mean, Petrucci and the drummer... gah... Only drawback is that their kind of boring at times. Another choice I think is Smashing Pumpkins. They weren't slouches instrumentally, the lyrics were great, the songs didn't all sound the same, and Corgan isn't a crappy vocalist.

Have To Be Red Hot Chili Peppers

Bad Religion Living End Social D. are up there

haha

I tip my incredibly pimp hat to you David Frost.

BAHAHAHAHAHAHAHA.

Red Hot's are a good one. Completely revolutionized new music. And just kick ass.

Smashing Pumpkins were a good band (and you're right about all that you said) but I wouldnt call them legends or anything.

I might lean towards someone like Queen. Or perhaps Rage Against the Machine. Imagine seeing them live..

I'm going to go with The Mars Volta. They are absolutley insane.

Every band has a bad album... unless they only put out one.

For this reason i have to say interpol.
Perfect album Turn On The Bright Lights

However, you didn't say it had to be metal or rock, even though it is in the rock and metal forum... Why was that anyways? Shouldn't it have been placed in General? Just a thought...
And they do suck live... but what do you expect?

Alice In Chains

Rolling Stones