Gaming headset:
Tritton Ax Pro. $180 for a real multiple speaker headphone for true surround. It was horrible.
The Turtle Beach Z2 was just as bad, even with 50mm stereo drivers. Not to mention, the first pair broke as I took them out of the box the first time. Yeah.
As far as headphones... I'd say the Koss UR40. Tried two of them, and it was the most worthless pile of excrement I've heard. People love to mod these, which would make them better, but I bought them before I knew all about the mods. In stock form, they are a disaster.
The Sennheiser PX200-II was also horrible. Not because it wasn't capable, but because it was impossible to get a good seal, that everything sounded tinny. It also didn't stay in place. What good are headphones if the seal is very important but the design doesn't allow it?
The Skullcandy Lowriders were also just... ugh.
The Panasonic HTX7. They looked nice, but that sound quality was lol-worthy. I honestly felt the sound quality was worth $5. I honestly can't believe people like this thing. I'd buy one, transplant some good drivers, better pads, and recable.
The Sony XB500. Bass and mud, 24-7. Sounds like they have the flu. Even EQ-ing the hell out of them won't save their disgraceful sound signature. The XB700 is MUCH better.