As a fellow metalhead, I love these guys. Although they're not everyone's cup of tea - my roommate says they're "too happy" to which I can agree to some extent. But not all metal has to be the opposite. I almost got to see them at my hometown, but the show was after I had begun my trip to San Diego. Alas, I'll be sure to catch them next time they're around here.
For those of you who don't really like the vocals or maybe are into power metal but DF doesn't do it for ya, please check out Manticora, Pyramaze, Edguy, and Dreamland. Just a couple of my favorites (and generally not from the United States, of course). Good stuff.