House Industries do have a head start when it comes to designing their email marketing because they sell beautiful products. As creators of amazing typefaces and now lovely iPhone apps, their content basically sells itself.
They do, however, make awesome use of scale in their HTML emails which works really well across desktop and mobile without the need to code a separate responsive version. There are a few points in this email where that falls down (sadly), because the CTA becomes tiny and the body copy (what little of it there is) is part of the images and gets scaled down a lot too. If these two aspects were attended to, it would be a great example.
(I would also suggest, at the risk of being branded a fun-sponge, that their cheeky unsubscribe copy is in fact too cheeky.)