What kind of headphones do you use? In-ear, on-ear or over-ear?
Over. Having a decently sized headset on-ear just never appealed to me since I wear it for hours at a time. I use ear buds (ie: in-ear) for non-computer use though - ie: 3DS and iPod music.
Who is the manufacturer of the headphones you use?
Sennheiser. Really good quality, though they aren't usually cheap to buy. I used to have a Microsoft one and I would have a hard time recommend any other headset for its price.
What is the model of your headphones?
PC320 Gaming Headset. Got it on Amazon for $101 when it's normally $161 (both figures after taxes and whatnot). I used to be in a gaming club while I was in university and they recommended this one. My old Microsoft one was the LiveChat LX-3000 and it was incredible for only $40. Lasted forever, durable and comfortable with extended use.
What do you think of it?
As mentioned above, I'm really happy with it. Sounds amazing, the cord's of a good length, the microphone is super clear and the volume dial's easily adjustable. My only real problem with it is the mute is activated by propping the microphone upward, which isn't convenient for me. Plus, when muted, it gives off a low-pitch buzz, which can get annoying if the person on the other end has the sound on in a quiet environment (ex: like when on Skype). Definitely worth what I paid for it though.