Here's a great route for being bumped- just golden. I'm going to try this in a few weeks to see what I can come up with.

MSP-PHX.

NWA flies DC-10's on this route, by and large.

On last Thursday, our 9:45 am flight (hardly peak time) was oversold, and I am a friend pocketed $300 vouchers.
On the 11:00 flight, we turned down $500 vouchers because we had an appointment.

On the way back Sunday, there again was a call for volunteers, but I needed to get home. The next flight was also oversold.

I was told by a MSP agent that this is among NWA's businest routes, and is a great one on which to get bumped.