What is your favorite board/cards/dice game?

As some of you may already know, I recently started a new job as a hotel entertainment manager.

I have decided to build up a collection of games, and would like some suggestions from people as to what kind of games you like.

So far we have:

4 x Chess
4 x Checkers
2 x Backgammon
2 x Poker Sets
1 x Boggle
1 x Rummycub (numbers version)
1 x Scrabble
1 x Yhatsi
1×1000 piece puzzle
1 x Jenga