I absolutely love the Borderlands games, they're so much fun! With a couple of different characters to choose from, you'll find something to fit your preferred fighting style. My personal favorite is the soldier with his turrets. My husband and I play this together all the time when we're bored. We've both beaten them multiple times, oddly enough it's one of the few games I never tire off. FYI, this is not a game for kids. Loads of cursing and violence, it's a great way to let off some steam!
The graphics are in this great comic book style which I didn't think would appeal to me, but it's actually pretty great. The first Borderlands is still my favorite, but these other two are worth checking out!