Ain't no doubt that inspite of all the great bands and artists that I'm mentioning here, Dream Thater is the most amazing band I have ever heard. As my musical evolvement has grown through the years, Dream Theater was the First Progresive Rock group I have heard. This new style of music was a little bit rough getting used to at the beginning, but once I got the idea, I couldn't stop hearing them. Every musician in this group is a phenomenon for himself. The extreme high technique of each and every one of them makes you grab your head and wonder "how the hell do they play this?" But it's not just their technique that makes Dream Theater a great band, It's also their talent to compose beautiful melodies that can make your skin get goose bumps, like their greatest masterpiece "A Change Of Seasons" which goes on for 23:09 minutes that never seem too long.
John Petrucci is the ultimate guitar player behind Dream Theater, and his high speed playing does not affect his ability to play with feel and emotion, a gift that not all of the speed metal guitarists have (like Yngwee Malmsteen for example).
Mike Portnoy on the other hand is an incredible, almost insane, drummer.
His playing style dosen't remind any other drummer that you've heard. His 'Purple monster' drum kit (as he calls it) gives him the ability to show what he can do with his hands and legs. And he can do a lot!