Don't get a gaming headset. They're too expensive and often lack the mic and audio quality you're paying for. Buy some good headphones (if you don't have some already). Don't get beats. Just something affordable and sturdy-looking. Also make sure the frequency response range is decent (the lower limit shouldn't be much higher than 20Hz if you want good base).
For the mic, I'd suggest a blue snowball. They're around $40, and they have great audio quality.
*EDIT*
Actually, if you want to save more money, get a clip-on mic. Some people suggest Zalman. I've seen people using them and they have really good audio quality.