Unfortunately the wife and I have pretty long commutes to work, 31 miles and 26 miles respectively, between the two of us we drive over 550 miles a week just going to and from work. So gas prices do have a big affect on discretionary spending.
Running errands such as grocery shopping, hardware store runs and the like will be more carefully coordinated so as to reduce the number and frequency of trips. No more golf or movies at the theaters unless deep discounts come available and more recreational time will be spent doing free or inexpensive activities like canoeing, fishing, and picnicking at the local park or lakes. The .22 rimfires will see a lot more action than the centerfires. Eating out will be cut back even further although we don't eat out often as it is due in part to my wife's dietary restrictions because of food allergies and lactose intolerance.
We also just purchased an 08' Toyota RAV4 that get's around the same mileage as my wife's 03' PT Cruiser. She is driving it now, I am driving the PT Cruiser and my gas guzzling Dodge truck will only be used for hauling trash, yard work and toting the canoe on the weekends. The PT Cruiser and the Dodge truck both have well over 150,000 miles on them so a replacement was about do anyway.
I think that whatever gains the country may have made in the economy will be squashed if gas prices continue to rise unchecked. No one is getting pay raises but the costs of everything will continue to go up with fuel prices. The increased costs of living coupled with stagnant incomes means everyone will have to tighten their belts to some degree, further stifling the economy.
Get ready boys, we are in for a rough road ahead.