Screen + Audio recording software?

What’s a good (free) program my friend and I can use to record 1) the computer’s screen and 2) talking from a mic? We want to make video walkthroughs of our programming this year but don’t know which program to go with

CamStudio

EzVid

MSI Afterburner, while not primarily a recording software, has a screen recording function that works very well, and you can set the input to microphone