okay, i only saw part of this one... and i only remember a few details.
here are my clues:
if i remember correctly, a son and his dad (or maybe a wife and husband?) are sitting at home. a vehicle pulls up in the driveway. the dad goes out to talk to the person. he comes back in to say he has to go somewhere, takes off in his pickup, and disappears. can't remember of he was found murdered or is still missing. the family swears he would have no reason to just take off.
any takers?

i remember being intrigued by this one, so i hope somebody can fill me in.

Yes I remember that one as it is one of my favorite "newer" ones. His name is Leonard Dirickson. Here is the UM profile:

http://www.unsolved.com/0151-Lenny.html

I thought it was so sad as they're interviewing his teenage son and his voice was quivering as he said that his dad wouldn't just take off and leave him. I don't think he's ever been found.

I don't think he's ever been found.

http://www.lutheranok.com/pray/intercession.htm

I came upon the link above after searching through Google. At the bottom of the page of that link, it mentions that there are "unrelenting" prayers for the safe return of Leonard Dirickson. The site's last update is listed as 10/10/05 (yesterday). Therefore, the current status of the case doesn't look good. :(