I think it's great. Most amateur site designers will go insane with all of these ridiciulously crazy graphics. It is very difficult to get it absolutely right.
Your best bet is simplicity. A cleanly cut website is the easiest to navigate and will load quicker. The lack of graphics on your website is what makes it work well.
The website banner just seems to be a bit too bland. It doesn't really look anything like a graphic but a meshed bunch of colours. But don't add too much to it, it will kill the website's working simplicity.
The bordering fade at the sides is growing on me a bit. It's just nitpicking, but it may look cleaner without it or a more dull one.