My friends and I play a lot of board games. Some of our frequent games are:
Battlestar Galactica: We generally play with six players. I love the series to bits and enjoy the hell out of the game. I've never won a game, but I still enjoy the holy hell out of it. I love the level of paranoia that seeps into our group.
Lords of Waterdeep: One of the newest games in our group and one we really enjoy.
Betrayal at House on the Hill: It's been talked about already, but it's a hell of a game that's easy to pick up. Our group experiences about 50/50 win/loss for survivors.
Marvel Legendary: A deck building game that we've recently started playing that's pretty fun. They just released an expansion for it. We randomly assign as much as we can, so sometimes it can be pretty challenging and other times it can be a breeze.
Catan: Classic board game and a good first step into the "geek" board games
Dominion: Been talked about. We don't play this as much, if at all, any more but I still think it's a great, easy game to pick up.
Roll Through the Ages: This is a quick to play, easy to pick up resource management game, but far simpler than many of them out there.
Love Letter: 16 cards and you're trying to get your love letter to the princess. Doesn't sound interesting right? The games we played of it might have been some of the most ruthless gaming we've done as a group. Accessible to lots of people.
Gloom: Card game. You start out with a family of misfits that you're trying to put negative modifiers on before you kill them while putting positive modifiers on your opponents' family and trying to kill them too. Each card has a title and we end up telling sordid, perverted stories based on the titles. One story involved one guy having an obsession with doing perverted things to little furry animals, finding a partner who was also into that, and then dying during an erotic session involving said animals. The cards just worked out. Lots of expansions, including a Cthulhu one.
Touch of Evil: Arkham Horror lite. Co-op vs. the board where you build up your characters, fight minions, and eventually a big bad. Apparently, the company pays the actors on the box to appear at cons dressed as their characters.
Arkham Horror: Great co-op game, but complicated. Ugh. Once you get the game down, it's a lot of fun. However, nothing is worse than spending two hours playing a game only to lose because the Old One is a beast.
Ninja Burger: Card game. One of those games where it's fun to screw your fellow players over at the last minute, but also one where one person gets ahead and the person in last place prolongs the game. Kind of frustrating if this happens when it's the last game of the night and it's 2am.
Chaos in the Old World: A Warhammer Fantasy based game that we've played a couple of times. At first, one of the gods seems overpowered, but once you get a feel for the game, each one has a distinctive strategy. We dig it, but don't play it much.
Cards Against Humanity: I haven't played it but the other guys have and they love it. Then again, we're a super perverted, messed up group of people, so it fits us like a glove. I did experience a very CAH moment in Apples to Apples where my brother-in-law played a card that said "Helen Keller" in response to a card that said "senseless". I laughed. He didn't win that round.
Those are the ones that come to mind as popping up most frequently.