Games we play, or have played at our Game Nights:
Munchkin - we burned out on this. We've got a boatload of expansions and honestly I think it could be fun since it's so damn easy to teach if I just caved in and customized the massive deck it has become, but it's very much a filler game that I think really needs a good bit of customization to make truly enjoyable.
Betrayal at House on the Hill - generally a crowd-pleaser; the game is a real blast (thanks to this thread for turning me onto it!), and if your group is okay with the fact that there's some real unbalance to it towards the end, it's a fine pick-up.
Zombicide - boy, does this game need work. It's a lot of fun, but custom rules are pretty much required to enjoy it. I spent a lot of time devising fixes to make this game better, and now we really dig it, but it's very much a game you play 1 mission of a night tops, because any more will burn you out fast.
Sushi Go! - the epitome of filler game. It's a fine drafting game that appeals to most anyone, but at this point, I only really bring it because some of our group members are nuts for it, inexplicably. (I find it to be the equivalent of cheese and crackers; a fine palate cleanser, maybe, but not a worthy appetizer.)
Coup - Love this game. The problem is it's super group-dependent; underlying relationships play out a lot in the game, and it's hard to encourage people to step outside of their comfort zone and forge new alliances sometimes. But, it's pretty fun, and relatively fast.
Eldritch Horror - This was something someone else brought; I didn't expect to like it (and I was mildly miffed since I was literally going to order Elder Sign that night, which is thematically similar), but it's actually kinda fun. It's definitely hard to say whether it's worth picking up, though; our first game lasted over 3 hours because the rules and goals made no sense (this happens any time I do not play rule keeper...), but after we understood it, the games since tend to clock in between 40 minutes to an hour and a half. The only bad thing is that there needs to be a few more cards; there's a point about 4/5ths of the way in (typically) where you start drawing the same cards you did at the start of the game, which makes everyone a bit annoyed if it drags on for too long. It's probably a fine game to whip out every couple of nights, though.
I know, glowing reviews all. I'm interested in Epic Spell Wars and that'll probably be my next pickup; we need more small/light games, because everyone always wants to play one of the bigger games first and then play light things for the rest of the night.