Peak oil/peak economy/peak climate to me means we first worlders will be getting a lot poorer. Buying an expensive new car may be OK for some, but no way I could possibly afford it on a peasant's salary.
My peak oil doom-mobile is a Kawasaki KLR 250 (pic is not my bike, obviously):
Cheap to run and easy to work on. I've already had to rebuild the carb and do other minor work, not that difficult. I think I can figure out how to fix almost anything else I'd need to keep it on the road. Ideally I'd get a junk bike for parts, but unfortunately the 250 KLRs aren't as common as the 650s, so I'm still dependent on the supply chain.
My old Ranger is a bit more difficult to work on, but still fairly easy compared to a Volt, I'm sure, and parts are cheap (I'm replacing the wheel bearings right now, ~$78 for both front wheels).
Gasoline is a relatively minor part of my vehicle expenses, insurance and maintenance are more expensive. I drive maybe 3500 miles a year, about a quarter of that on the motorcycle---even $10/gal gas wouldn't break me, though I'd probably do a better job of consolidating my trips.