Hand sewing?

What is the strongest stitch?  I have a really long car ride coming up and I need to keep myself busy (nope I am not the driver) :-) Anyway I was hoping to get some fabric and sew a little by hand while being bored in the car lol.  I would therefor like to know which stitch holds up the best for clothing and quilts if they would be different answers.

Thank you all very much!!

That's a really good question!  My first thought would be a backstitch. 
Ahh I just did a search and it appears that is so according to this site.
http://www.alternative-windows.com/stitches.htm

Enjoy the car ride.  I love choosing handwork to take along while DH drives.