Another thing to factor in is the strength of the Dollar.
I was just looking at the European gas prices. I was in France last summer, and gas would cost an average of EUR 1.35 per liter (EUR 5.13 per gallon). Today's price is floating at around EUR 1.55 a liter (EUR 5.89 per gallon). This gives us an increase of 15%, when dealing in Euro.
Equivelent dollar prices would be $1.82/L ($6.92/Gal) a year ago and $2.44/L ($9.27/Gal) today, giving us an increase of 34%, which is the sort of increase we've seen in North America over the last year.
What actually worries me is that if this were to continue, and gas reached unsustainable prices (over $2/L or $7.60/Gal), we wouldn't be able to simply follow the Europeans and settle for smaller cars, bicycles, mopeds or buses: the American city concept is fundamentally different than the European: lots of suburbia with little public transportation and vast distances to cover. For the most part, you can't even walk to the local Walmart. Europe, on the other hand, is much more compact and dense, and their public transportation system is much more developed. In Paris, I could easily take the Metro and a train to the Airport, arrive in rather short time and be happy. In Toronto, taking public transit to the airport would take me 2.5 hrs (vs. 30 minutes by car) AND the savings are rather small: I'd only save $2.50. My 2.5 hrs are definitely worth more than that!
Personally, I don't see a feasible alternative to my ES: I can't comfortably fit in a Civic or Corolla, taking the bus would cost me an average 2 extra hours of the day, and I'm not within a walking distance to anything, really, especially in the winter. The only thing I can do is suck up the 30% higher gas bill, and spend less on other things. Which, as mentioned before, will have a ripple effect in the Economy.