I own a whole closet full of board games, I'd have to go looking through but there are some really good ones. I tend to like complex games and these are some off the top of my head
I like the Game of Thrones. Very political, lotta wheeling and dealing, great with lots of players. Games last a long time. Combat is kind of like Diplomacy if I had to compare it to something but also feels like Risk with a whole lot more rules.
http://www.greatboardgames.ca/a-game-of-thrones-the-board-game.html
Zombicide, fun game, its co-op vs the game. Can be hard.
http://www.greatboardgames.ca/zombicide.html
Agricola, its older I think, a lot of strategy
http://www.greatboardgames.ca/agricola.html
The Resistance. I havent played it but it would fit into your traitor kind of game, plays best with a pile of people
http://www.greatboardgames.ca/the-resistance.html
Also I order all my stuff from that website, prices are good, they have tons of shit. Shipping is a flat like $10 so if you order make sure you get a bunch of stuff :P