Settlers of Catan is one of my favorites.
7 Wonders is a fantastic, wonderful game. It's like a combination of Catan and Civilization. Not so much a deck building game like Dominion. Check out this video review - http://www.youtube.com/watch?v=Cjv1JfFeQko
Risk is one of the all time greats.
And I have a soft spot for the old school games like Sorry!, Chutes and Ladders, etc.