I live in Sweden (population about 8,8 million) where the gas taxes are high but they have been raised gradually, it is thus hard to give any kind of before and after comparision. They have been more fiscal then enviromental, they are a sizable part of the goverments tax income. We have had the problem that alternatives to gasoline and diesel have been taxed into oblivion as soon as they start to be competetive, that might change now, I hope.

About 71-73% of our gasoline price is tax.

The main trend here is that people are moving into cities or rather city areas with more then about 200k in population. These city areas are then expaning outward along the train routs with lots of train commuting to smaller old towns that starts to expand instead of contracting.
There is a simmilar reach for car commuting but it do not reach as manny km as fast train commuting.
There is a "counter current" of people moving out of the central towns to rural areas around them. Most of these are people looking for a place to have a few horses, more scenic surroundings or less neighbours around them. If I look at a detailed map of the area around Linköping where I live I find that there are single houses or small clusters of houses almost everywhere with a distance between them of about 500-1500m.  

The more "rural" areas do of course depend 100% on cars, there are public busses but mostly as a bonus as there anyway is a need for buses for schoolchildren. Public transportation in towns and between towns are in general good or exelent. It is thus not common to have more then one car in a family if you live in a town.  The public transportation is about 50-75% tax financed wich unfortunately gives a lot of the problems associated with centrally planning. The gas price hurts and is now almost even with the capital cost for a second hand car, but I do not get a feeling that it menas that much for the car purchases.

Most towns and all cities have district heating systems. The main fuels are garbage, forest biomass and oil for peak loads and soon fossil gas. This is cheaper then having a chimny in each house. Manny of the larger units and all large new built ones are combined electricity and heating plants. The main heating methods are otherwise, wood, wood pellets, direct electricity and electricity used for heat pumping. Oil heating is fairly quickly going extinct, this has a lot to do with the taxes. Electrical heating is popular since we have had very low electricity prices due to overinvestment in nuclear power. These prices are now risind due to electricity export, more demand and green party i****s closing 2 out of 12 reactors. But the 10 left are being uprated to give as much power as we had a few years ago.  (The production is about 45-50% nuclear, 45-50% hydro and 5% misc. )

Another intresting trend is district cooling systems. Exess heat from garbage incineration plants is used during the summer to produce chilled water that then is distributed in city centers replacing small cooling systems in the buildings. No CFC, it do cost a lot in investment but is then cheaper to run and more electricity to export and the pipe network has a life lenght of manny decades.

Bicycling is slowly becomming more popular, among students it is mandatory since 90+ % of the students cant afford a car. In my town we have a network of bicycling roads and roads with little car traffic that if it were a grid would have sides of about 400m. All roads in built up areas exept the most tiny ones servicing a few houses do of course have sidewalks. An odd system fault is that you are not allowed to bring bicycles on trains.

The use of E85 ethanol/gasoline blend is growing very fast, more then 200 petrol stations have an E85 pump but most of the ethanol is Brasilian.  There is a potential to locally produce biomasses based fuel for about half of the current car and truck fleet, we do have a lot of forests and a fairly small population. In Linköping, population 130 000 we have a methane plant using waste biomass from food production and manure that produces about 5% of all the fuel sold, it is at least enough for all of the local busses.

Another energy related major investments is in the railway network wich gets about half of the government transportation infrastructure budget. All major railway lines are electrified.

There has been and there are some municipials that make it very hard to build "dispersed" housing, trying to concentrate the new buildings in dense areas for easy public transportation, etc. My impression of that is that it mostly leads to a slower economical development for that town. People do anyway cluster a lot where they can share infrastructure as long as they get the benefit of the savings.

My guess is that Sweden will handle peak oil gracefully. On average we will become poorer in absolute terms but richer when compared to most other countries. I do not think there will be any drastic lifestyle changes here, only gradual ones.