Les Schwab for me (the the NW)... prices are OK, but they made me a believer in service:
I was loaded with a 9' truck camper, 65 miles of gravel out of a small town in Idaho along the Middle Fork of the Salmon River. I rounded a corner near a mine and totally ripped 2 tires open. No cell service, and facing a multi-day hike out, a Forest service truck picked me up, took me to the local Schwab, and they drove me back 65 miles with free replacement tires. They put them on the truck and it cost me nothing... NOTHING! I offered cash for the effort, beer, food, etc. but I was told "this is my job - glad we could help".
That sold me!