i play board games quite regularly, they're fun ^^
The one i've played most, and one of the best out there, is Settlers of Catan. Nice simple rules, lots of variation, and a good amount of player interaction.
Carcassonne is also very nice, easy to learn and a fun quick game.
Ticket to Ride has been mentionned several times, and i play that too.
And i want to mention Dominion, a card game, with several extensions, a bit more difficult to learn but with a nice degree of complexity and a good balance of chance and strategy.