I "shop around" for a lot of things. This last month, I "shopped around" for a new digital camera, wigs, and a sewing machine. For the digital camera and the sewing machine, I had to decide what would meet my needs. Once I picked a product, then I did some price comparison shopping using the internet. The wigs, on the other hand, I didn't do much price comparison- I only looked around for where I could get good quality wigs for costuming.
When I expect something to last me a long time, I first comparison shop between products so I know exactly what product I want to buy. Then I do price comparisons between vendors with a good reputation. This is my method of shopping for cars, anything electronic, furniture, etc.
For most other things, I don't price comparison shop. Driving around to find the cheapest gas negates the savings if you have to drive ten miles to save $.02 a gallon.