Gas Prices - Sweet sweet crude.

Gas is over a dollar a litre again where I live, which is really just a psychological barrier, but annoys me at the same time. It's one of those obvious expenses that I notice almost every day. I don't drive around town looking for a grocery store that has milk for a few cents cheaper per bag, or bread a few cents less per loaf, nor do I complain if a green pepper costs me $1.27 per pound this week when it was $0.99 last week.
I looked at my finances from last year, and I spent a little more than 3% of my net income on gas. I spent more on insurance for my car. I say this because I suspect that a lot of people are in a similar situation, and that while it sucks to have to pay more for gas, there's certainly room in my budget for increases. How high will it have to go before I start changing my driving patterns, style and habits. How high will it have to go before 'society in general' begins to drive less, drive smaller cars, walk more, bike more, use transit more, etc..?
I try to think 'green' and when I bought my car a couple years ago one of the main selling points for it was the fuel economy, both because of economic benefits, but also reduced environmental impact. But, I'm sure I could change a few things around so that I drive a bit less than my 20,000km per year. I could use my bike more in the summer, and I can walk to work year round, if need be. The only stuff I really need to drive for is getting to church (on the other end of town), and visiting my parents or friends who live out of town... Anyway, I'm curious to see how my thinking on this will have changed in a couple years when oil/gas continue to climb as we continue to drain our planet of all things sweet and crude.