I purchase mine from Discount Tire just because they have locations all over the country in case something happens to a tire. I haven't had any issues with them and they also price match. They also offer free rotation and balance if you purchase the tires from them.
Les Schewab. They take care of all the work needed and offer their warranty on top (costs a little more but piece of mind to have to replace punctured tires with no questions asked) if you drive on constructions sites all the time like me
I've purchased my last few sets of BFGs through Tire Rack. They ship fast and have a nationwide network of installers. The locals who do it here are great. Tire Rack ships directly to them and they take care of the rest.