Budget: up to $400 used
Main concerns: blocking sudden sharp noises; active noise cancelling is not very important, because the only constant noise is a fairly benign air conditioner, but there's lots of talking, coughing, typing, etc. I also need a set comfortable enough to wear for 4-8 hours a day.
Musical preference: Mostly jazz, some rock.
IEMs aren't really an option. I have some that I use at the gym, and while they do block a lot of noise, I can't wear...