Porcupine Tree. The first song I heard from them, Wedding Nails, almost made me crash my car because it was so awesome. To this day I still love that song. Sadly, every single other song they wrote is nothing like that. Everything else is so slow and mellow and stuffy-sounding, not at all energetic or fun to listen to like Wedding Nails.
And before you start yelling at me, I know what prog is, and I know that their "stuffiness: is from their exquisite knowledge of music theory and odd time signatures and all that, and quite frankly, it bores me. Their music is not fun to listen to.