Quick Headset Question

So, I just finished ordering my new build and I have a question about my headset situation. I use to play games on a laptop, so I just used the mic on that and a basic headset(not the best but not bad at all). Anyways my new build is a desktop, so no build in mic. I have some old crummy USB headset with a mic on it though, so my question is can I use my headset without the mic for my audio (btw it's a standard 3.5mm headset) and my crappy USB headset with a mic for the microphone. And finally I'd like to ask if anyone knows of a good headset for gaming that is also comfortable after long hours of use. I have started to play a lot more competitive FPSs so it must have good sound. I need to save some money, but so I'll be able to get it in a month or so, but my budget on the headset is $200.Thanks for the help.

I would suggest this setup

http://www.amazon.com/Audio-Technica-AT2020-Cardioid-Condenser-Microphone/dp/B0006H92QK/ref=sr_1_2?s=musical-instruments&ie=UTF8&qid=1394593194&sr=1-2&keywords=Condenser+-+Audio+Technica+AT2020

http://www.amazon.com/Audio-Technica-ATH-M50S-Professional-Monitor-Headphones/dp/B004ZG9TMA/ref=sr_1_3?s=musical-instruments&ie=UTF8&qid=1397026663&sr=1-3&keywords=Audio+Technica+AThm50

My question is how are you going to pull this off, are you going to wear a pair of headphones and then the headset around your neck? If that's what you wanted to do yes you could run a usb headset just for the mic and route the sound to your onboard sound where it would come out the 3.5 jack. Confused as to what you're going to do exactly, also it's less confusing if you call headphones headphones and not a headset a headset will have a mic on it.

So now the question is with $200 what do you want a "headset" or a pair of "headphones"?

First off, sorry about the confusion, it was late when writing this. To pull this off I was planning on wearing the headset around my neck, and use the headphones for the actually sound that I would hear. Also, the $200 is for a headset, unless you could find a good pair of headphones and a desktop mic, but they would have to be pretty nice for me to consider that.