There are many famous drupal sites out there. This is a showcase of drupal sites that you can check and see for yourself what the CMS can actually do.

The New York Senate. Simple, elegant drupal site.

The Spread Firefox website of course. Great drupal showcase, great cause :)

The New York City casts another vote for drupal with the New York Observer website. Not so drupal-ish, but it's cool.

You would think that New York City is the most drupal-friendly city but you would be wrong. The official website of the City of Athens is built with drupal, and so is the Visitors website of the city, breathtakingathens.com. Two (official) votes from Athens. (and there are many more)

The Amnesty international website is built with drupal, a great showcase.

Miami also is a drupal city with www.miami.com website. Very nice work, very informative.

MTV uk has a wonderfull and feature-rich site, on drupal, a must see: http://www.mtv.co.uk/

Ubuntu is the leading linux distribution at this time, and having extensive knowledge of the opensource platforms ;) they chose drupal to run their official website

Sony's myplay.com is another impressive drupal showcase. A little flashy for my taste, but that's how it is.