Here are the games that acquired the most new players between Thanksgiving 2010 and Thanksgiving 2011, ranked by the number of players (*minus 500 if the game is showing up for the first time as having more than 500 players ever).

7 Wonders is pretty clearly the de facto game of the year. The others are a nice mix of new games and evergreen titles, all worth considering as Christmas gifts.

6605 7 Wonders
2652 Dominion
2421 Forbidden Island
2162* Resistance
2131 Carcassonne
2127 Agricola
2093 Dixit
2084 Alien Frontiers
2057 Small World
2019* Sid Meier's Civilization: The Board Game
1960 Dominant Species
1945* Troyes
1921 Pandemic
1890* Quarriors!
1874 Settlers of Catan
1734 Puerto Rico
1700 Stone Age
1676 London
1655 Glen More
1641 Power Grid
1631 Race for the Galaxy
1609 Survive: Escape from Atlantis!
1596 Innovation
1583 Ticket to Ride
1525* Mansions of Madness
1521 Citadels