What are your top 10 (or any #) functional websites? your favorite websites?

the most practical, useful, or otherwise best sites you know about -- it doesn't matter exactly how many, or the order or anything

for example:
google.com
fluther.com
couchsurfing.com
maps.google.com
craigslist.org
commondreams.org
dictionary.com
mapquest.com
511.org (if you're in the Bay Area)
flickr.com
youtube.com
wikipedia.org
etc etc etc