I like them, but after reading through this thread I think I have a pretty unique situation.
My fiancé does not have a lot of friends our age. He has always been somewhat of a loner and does not like conventional things other people our age do. He has a group of friends from childhood and we all hangout once or twice a month. They are at different points in their lives (some are dropouts, others are still in college, some have started their careers) so they've drifted apart somewhat but it's nice everyone still makes an effort to get together. Only two of them have longterm girlfriends but they always include us when they get together.
Other than that, my fiancé has older work colleagues we sometimes do things with on the weekends with their families.
One thing I really appreciate about my fiancé is that he has always made an effort to include me in social outings with friends and colleagues at his own behest. He's a good fellow.