My favorite board game of all time has to be Cosmic Encounter, Mayfair version. That game's a recipe for chaos. I also enjoy those crazy six hour strategy games like the Lord of the Rings game.
Games the people I hang out with now play more often are things like Settlers of Catan, Carcassone, Ticket to Ride, Citadels, Seven Wonders, etc. Half strategic, half random craziness games that last 1-2 hours.