Really well done. Kind of reminds me of Threadless - the tshirt company site. Not a bad thing. I really like the design and the concept it pretty cool. Keep it up. I would say for what it is 10 out of 10. You may need more features to keep people coming.
It's a simple design as you said, and I enjoy looking at simple sites. With growth though, your site could become quite confusing as Alex said. The simple logo and navigation was great! Also loads quickly. :D