Those guys use fraps. With a mic, you'll be fine.
The real thing that people want is HD quality and a solid framerate, which fraps can do both.
Also, for livestream, get a twitch.tv account along with the software Xsplit. It has a wonderful framerate and twitch is a great host site.

Goodluck on the gameplay, just remember to be yourself, if people wanted tobuscus, pewdiepie, or yogscast, they'd watch them

Thanks! I got the idea a few weeks back cause i bought a game and was playing it with my friend and imo, we were hilarious. Also i enjoy yogscast and pewdiepie and think it'd be pretty cool to have people watch my stuff

I use WeGame. If I want live commentary, I turn on the "Listen to this device" function in my mic's dialogue box