Check out Chicago-based agency Palantir's website for a great example of responsive Drupal-powered goodness.
Palantir is a full-service design and strategy agency based in Chicago, which specialises in Drupal-powered development. It’s hard not to fall immediately in love with this site, with its charming retro space-themed illustrations, gorgeous colour palette and beautiful typography. The spacious layout is a welcome feature too, though it could be tightened up on smaller screens.
Homepage requests/size: 26/1.00 MB mobile, 26/1.00 MB desktop