I was recently asking about a gaming headset myself on another forum and got a pretty good answer. I'm just going to copy and paste his answer.
Well hellooooooooooo my favorite thread that resurfaces so often, I've missed you. It has been a while, how nice of you to keep in touch.
"First things first:
What you don't want to do is buy anything (for the most part) that is labeled a "headset." Most products on the market labeled as headsets use cheap mics, cheap headphones, put them together and price them at a huge premium.
The majority of headsets use mics that you can buy yourself for $10-15. So what I recommend, as I do to everyone, is to buy yourself one of these cheap mics and pair it with a really good set of entry level headphones like the HD 555's or HD 558's.
The 555's you can open up the ears to and pull out a piece of foam that will make them sound like the higher model 595.
However, usually this combo won't run you more than $100-120 total, but for some reason it will right now. If you can't find the 555's for 100-120 somewhere else, then I would recommend the PC350's mentioned above. They are one of the only "headsets" I actually trust, but that's due to the brand name and that brand caring more about sound quality more than anything else. Most microphones will give you the same voice quality, there really isn't too much difference in that department. So my suggestion is always go cheap on voice and big on sound.
Try to avoid Razer and steelseries products. They are designed to last for a certain amount of time (sometimes less than a year) before they inevitably fail. I went through hundreds of dollars of cheap headsets from the 20-80 dollar range before I finally grew some balls and invested in something that will last. Beware though, once your ears feel the difference, you'll want to spend more. My current phones are the HD 650's and boy are they godlike.
Happy hunting. "
This was from Boyiee over at Bluegartr.com