Things That Drive me Crazy - Grammar Sez Who or That?

This is excerpted from Grammar Quick and Dirty  
by Mignon Fogarty - check this out and go to the link above for the rest of the story -

Today's topic is who versus that.

Lesley called in with this question:

My pet peeve is who versus that, as in “You know Bob, he's the guy that sold me my car.” It drives me nuts. Or am I mistaken and it's just become part of the new English verbiage in the evolution of the language?

I kind of talked about this question in episode 7, but other people have also asked the same thing recently, including Corinne, so I thought it would be worth going into a little further.

The quick and dirty answer is that you use who when you are talking about a person and that when you are talking about an object. Stick with that rule and you'll be safe.