So I was recently in the market for a pair of open back headphones, and after hearing praise of Sennheiser for their offerings, i decided to purchase the HD 518 with my budget of about 100 dollars.    I think that the design is something you love or hate, and personally i love it. The louvered sides look quite nice to me, and the Sennheiser logo in the middle just looks elegant. The earpads are made of what i can only think are some sort of cotton material, and they're exceptionally soft. They aren't the largest however, so if you have ears that...