They had a conversation about that on Sirius NFL. You'd think a team would want the ball starting the second half, so if they score last in the first, they'd get the ball back again. Just like Highway said, the reason they take it first is the momentum of scoring on the opening drive. Seattle's had great success with that, as have the Colts. It's a psychological effect for both teams if the winner of the coin toss scores on the opening drive.
"If I claim to be a wise man, it surely means that I don't know." - Kansas