I recently bought Dream Theater's albums "Octavarium" and "Train of Thought", and I don't think I've ever listened to more than one album from a band all the way through. They're truly inspiring musicians, and I feel that even if you don't like the metal genre, you'll like at least a few of their songs.
Video related, my favorite song off of the two albums. After you get past the gritty 10 seconds of the intro, it gets to be a very mainstream-friendly song. If you explore the band a little more, I'm sure everyone can find a few songs you like from this amazing band.