Hi, I know quite a few people on here do Portal 2 playthroughs and I was just wondering what software everyone uses to record the gameplay?

Thanks.

Most people use FRAPS. I actually use WeGame, because 1) it's free and 2) it's free. However, if you want a high-quality recording, you're probably best off using the Source Recorder (there are a fair amount of tutorials floating around the Internet); it involves recording a demo and then telling the game to record as you play back that demo.

You could always use XFire. It has an in-game recorder, and a live broadcaster as well.
It does take up a lot of space for a couple of seconds recording though :S

XFire is also free.

I use fraps because it works well and I've already purchased it.

I use the engine itself because I'm cheap. First Read this on demo Creation
Then read this on video rendering