Having already given my top three, I think I'll offer some unsolicited oppinions of other people's picks
The Smashing Pumpkins: I don't know how I feel about them in general, but they definately did some of the best individyal songs of the '90s (and, having only thought about it, I'll have "Today" stuck in my head for hours)
The Doors: I was REALLY into these guys when I was about 15. AT teh time, I was convinced that Jim Morrison was ultra-cool and brilliant. I grew out of that pretty quick, but my appreciation of Ray Manzarek and Robby Krieger's musical tallenst only grows with time.
Aerosmith: One of the few "classic" bands in existance that I actually like MORE for their newer stuff than the "clasics" (though the Crazy/Crying/whatever-the-other-one-was power ballad thing could have easilly ruined it)
Switchfoot: I didn't really like them at first, though now I can't recall just what it was I thought I had against them (ever had that happen to you?). I like 'em fine now.
Pink Floyd: Duuuuuuuuuuuuuuuuuuuuuuuuude!
Cool!
Evanescence: I'm iffy about them. I admit that I have heard some pretty good album tracks, but I've hated all of their singles so far.
Jars of Clay: One of my favorite Christian acts of all time (just about a half step behind PFR in my book)
Puffy AmiYumi: As of late, probobly my favorite Japanese group. *hums the theme to their new show*
The Beatles: You go, dude!
Weird Al: Ah yes, I can still remember the first time I heard "Jurassic Park." Changed my life, it did!
NESkimos: Huh, I've never heard of them beofre. I'll have to look 'em up.
Rebecca St James: Very cool. She's alwasy goot really unique melodies in her songs.
CCR: This is kind of random, but I love listening to them whenever I'm traveling someplace. Good music for crusin' down a highway somewhere. Makes me feel almost cool...