Yeah. My first thought was that buying tires online seemed rather sketchy, but if I walk into a dealer or a local tire place, they're going to stock maybe 3 or 4 models that fit my car, and be able to order another 7 or 8 models. When I go on Tire Rack, there are 30 or 40, and I can filter them by whatever, see the speed/traction ratings, and get subjective reviews from people who've already driven on them, some of whom have even done so with the same model car I own. When you factor in the price difference, it's a no-brainer. They have a lot of installers too, at least in my area.

Oh yeah, pay attention to their warranty ratings, too. They do a good job of evaluating which waranties actually mean something versus the ones that don't protect you at all.