I also love the Graverobbers game... I have the original plus Skippy's Revenge and Cannibal Pygmies, and I think my sister has the Kung-Fu one.
Arkham Horror is one of my favourite board games ever, because of the cooperative nature of it. I've tried a coupole of the expansions for it as well. If you like Mythos stuff and have a fair amount of time, its really really fun! The Game of Thrones game is also fun. Pandemic is also great, but very hard! I played Nuclear War (and the other expansion) for the first time a little while ago also, and it was a ton of fun
Some friends of mine I visited in May have the OOtS game, and we played it twice but never had enough time to finish a game - it was looooong, but fun.
While I was in the field I got introduced to a fun card game called Quiddler, which is sort of like what would happen if Scrabble and Gin Rummy had a baby. We also played a ton of cribbage, but that is maybe not the right kind of board game!
And the last one worth mentioning is probably History of the World, which is one of those conquor the world type strategy games, but it progresses through time. I used to play that fairly regularly with some of the other people ion my department when I was getting my MA - we'd meet up for nerdy history games ever second Friday or so - good times...
Oh no, I lied, one more - bananagrams