I'm obviously going to be in the minority here, but I don't find the quality of lumber from Home Depot or Lowes much different from the local stores that I have available. I'm about an hour from Lowes/HD, and if I just need a few pieces, I always buy locally for convenience. When I started my 1,500 sq ft addition, conventionally framed, I got quotes from the local yards and Lowes/HD an hour away. I ended up with Home Depot: they were the lowest price, including free delivery, and were far and away the friendliest of the group that I dealt with. The local stores claimed to be giving me "contractor" pricing, and Lowes and HD both game me quotes from their "bid room", which to me seems to be about 10% to 15% off normal.
The lumber that was delivered, not hand picked by me, was as good or better than expected. All the boards had four good edges, clear and straight (although I will admit that some of the treated lumber began to twist after a little while, but I don't know of treated lumber anymore that doesn't.) In addition to the lowest price, friendliest service, and best delivery, they also kicked in some extra pieces of lot of lumber, including 5/8" plywood that I used for the roof decking, and the both the lady at the store and the delivery driver reminded me that if I found defective (warped, split, etc.), then I could bring them back to the store and exchange them.
I know that this story sounds like I'm a plant from Home Depot/Lowes, but I can assure you I'm not. I just had a really good experience and thought that I would share.
Good luck and take care.