The Scale Model of the Solar System (from phrenopolis.com) shows both the relative sizes of the planets and the Sun as well as representing the distances from the Sun on the same scale.  This image is huge (just over half a mile wide), and as you can imagine mostly black.

This page shows a scale model of the solar system, shrunken down to the point where the Sun, normally more than eight hundred thousand miles across, is the size you see it here. The planets are shown in corresponding scale. Unlike most models, which are compressed for viewing convenience, the planets here are also shown at their true-to-scale average distances from the Sun. That makes this page rather large - on an ordinary 72 dpi monitor it's just over half a mile wide, making it possibly one of the largest pages on the web. This means you'll have to do a bit of scrolling if you want to find the planets, but don't despair. They are reasonably bright and labeled, so you can probably catch them flashing by in the blackness even if you are scrolling fairly fast.

Found on Information Aesthetics.