If you have reason to suspect they are drunk, I would let them hit more. That way, there's more of a chance of them stopping (especially if it's a hard hit), which means a far better chance of them getting locked up. I personally try to avoid swerving to miss anything, as the chances of something worse happening (like in your situation) are too high. I've been known to swerve at cars on the highway if they are having trouble staying in their lane. I have no problem with causing someone else to wreck if they aren't driving safely to begin with, at least it would get them off the road for a while.
As for my stories....I was sitting in a ditch facing the way I came from about 3 hours after I got my drivers license when I was 16. I hit the gas too hard too early in a turn. The tow truck driver thought it would be nice to call the state highway patrol, so I got a ticket for failure to control.
Second one was about 3.5 years ago. I was screwing with the CD player and didn't notice everyone in front of me slamming on their brakes. I managed to bleed of some speed, but i still rear ended a full size chevy truck at about 30 mph. I bent the frame, pushed the fan into the water pump, and needed every body part in front of the firewall replaced. I got the truck back a month later. The truck I hit needed its bumper pulled back out a little bit, but was otherwise fine.