Looking for a good headset for gaming

I do not know what to look for, but what I do know is that I would like a headset that can work for PC and Xbox360. If there aren't any suggestions that you have onhand, could you just give me a little bit of details that I should look for? Thanks for the help. :)

Here's some razor and steelseries ones:

http://store.razerzone.com/store/razerusa/en_US/list/categoryID.57047900

http://steelseries.com/us/products/audio/steelseries-spectrum-7xb

or you can buy a regular steelseries/ect headset and use this:

http://steelseries.com/us/products/consoles/steelseries-spectrum-audio-mixer-xb