Soldato
It's a utterly superb news source and gives you a overview of what is happening on this little rock we call Earth.
This. It's become the pulse of the Interwebs. I use it to keep in contact with friends (when used with @FourSquare this becomes even more useful) )as well as follow certain people in the Tech industry.
If you use it just to post that you've had toast or to follow "celebrities" then you're not using it right.
@LordSplodge