Since there've been many posts, here are my impressions:
I live on 82nd Street between 35th and 37th Avenues. Our place is in the back, so we literally hear no noise whatsoever, despite being on a bus route. 37th Avenue, and 82nd Street, as well as the area around 74th, tends to get messy during the day, but go beyond those blocks and it's clean. I actually prefer living on 82nd because in the morning, I stand on the subway for one stop, and then many people exit at 74th, so I almost always get a seat. Been here over 15 years, and I can count on one hand the times that I didn't get a seat.
We moved here when we were in out 30's. We're a gay couple, but not much into nightlife, so this suited us. When we were in our 20's we lived in the East Village. If you go out at night, and still want to stay in Queens, try Sunnyside as the nightlife is better there.
As for safety, as a guy, I've never been scared. Having said that, I also never go on Roosevelt after, say, 11 p.m. And the residential streets can get spookily quiet at night, so if I was a woman, and someone was following me on them, I'd have my guard up. When I find myself in that situation, I just sing along to the music on my headphones just to make myself known so the woman won't think I'm sneaking up on them. Most of the times, I get a chuckle as I pass, but better than scaring the crap out of someone.