Have just ordered my second set of tires through Discount Tires Direct. Have found them to offer cheapest prices (my 225X55X17 set cost $65 per tire). Price includes free shipping (takes 5-7 days to arrive, nicely wrapped so easy to store and transport). I get installed and balanced for $15 per tire.
Have send a number of friends to the site; none have been disappointed.
I have now purchased 4 complete sets of tires from Discount Tire Direct and will probably use them again in the future. I have found the prices to be very competitive, especially if you are able to purchase them with one or more of the many rebates they offer. The shipping is fast and you can have them shipped to one of their stores or directly to you, whichever is more convenient.
The only reason they don't receive 5 stars is their rebate process is so convoluted. They require you to fill out additional forms entering again, and again, information they already have in their system because they just sold you the tires. You must upload the receipts (again, for tires they just sold you online) and a few times the upload didn't work so all the paperwork had to be mailed to them via snail mail. It appears to me they make the process purposely complicated, knowing a percentage of people will just give up. I still recommend the site, just know you are going to really have to work for any rebates.