Three Legged Legs are Greg Gunn, Casey Hunt and Reza Rasoli. Watching their work as a whole you immediately see the breadth of visual styles they are capable of, with the common thread being an immersive and layered world contained within each piece. You feel like you could fall headlong into each little world, which only enhances the storytelling possibilities. From the first frame you feel like just about anything could appear around the corner and it never gets boring.
See their repertoire here.
And here's one of my favorites to get you started (I wanted to post the Zune spot, but the audio has been stripped from the Youtube postings of it, so be sure to check out the link and watch that one):
