Surround sound is obviously good
Switching between Surround Sound and a standard setup really depends on what you plan on using the headset for. Surround sound is ideal for gaming, but stereo allows for better music quality. Having to pack multiple speakers in each ear cup limits what they can do
but headphone frequency response?
Microphone impedance?
Lower is better and normally indicates a higher quality microphone. It really doesn't effect to much until you get into longer cabling though. Not normally an issue with headsets
Signal to Noise ratio?
This is fairly obvious but it is the ratio of signal in relation to the noise in Decibels. The higher the number the less background noise you will find.
Connector types
3.5mm is the way to go. 3.5 is for some phones, 6.5 is used in home and professional audio equipment
is USB the best option
USB means the sound card is built in. The built in USB sound cards normally have about the same quality as the built in audio on your motherboard. I personally hate them. I would much rather be able to swap my headset out without having to install or run any other software. THe upside is if you have standard onboard audio USB headsets sometimes have a few more features as far as voice morphing and other similar things. It seems a lot of the USB headsets use generic and sometimes buggy software, but that experience depends entirely on the headset.
headphone and microphone sensitivity
Higher sensitivity means louder. Sensitivity is a measure of how many decibels are produced for each mW, the higher the sensitivity the more efficient your headset is at outputting sound.
