Over ear meaning around ear? Also do you mean your home desktop PC? Because if it's a desktop I'd assume it's ok to have the headphones be open, where if it's your laptop you'd probably want closed.
Nothing beats the Grado sr80i at the $100 price point, in my opinion. Those are open, on-ear headphones. You can get Sennheiser 518's for that price. That's an open, around-ear headphone. Very different sound than the Grado, but still a nice well rounded headphone. If you want closed headphones you might want to save up and spend a bit more. You can get a pair of Ultrasone pro 550's for about $150. Those would be my recommendations.
Have to agree with the sr80i recommendation. I have not yet heard a better headphone for the price, and they are sturdy yet lightweight. So long as you aren't looking for a closed back I'd say they fit the bill perfectly, though they do have lower sensitivity than other portable headphones if that's a concern.