Big ticket items, like a car or computer are a couple of things that I will not purchase online. Somethings, you just have to see and touch in order to make the right purchase.
Anything that has a size involved: shoes, clothing, coats. Even in the stores sizes vary from one manufacturer to another. I also wouldn't buy a car online unless it were somehow new & directly from the manufacturer but I would checked it out in real life somewhere before making the purchase.