Stagecoach is about 1.5 hours from me. I usually make at least 2 trips a year.
We are a retailer for JT International, so a lot of my odds and ends tack and supplies are from them 
NRS is my favorite.
Rods
MC Diamond
SS Tack
Rods
Valley Vet
Teskeys
Jeffers
Smith Brothers
State Line
Chicks
Tack Stop
Around The Barrel
US Rodeo Supply
Well, when I am in need of a 6 inch bit, English or western (curiously my appendix qh, just a hair over 16 hands, has fat lips and needs a 6 incher, go figure, my bigger warmblood did not) I go to
I bought my bosals and good ol’ fashioned canvas topped wool saddle pads from Big Bend Saddlery:
http://www.bigbendsaddlery.com/home.html
I wanted a new fiador and a new pair of the cotton bosal colt starting reins, and they were only ones in the universe that seemed to have them, but I am well pleased with what I got from them, several years ago now.
Latest western saddle came from here:
http://www.highqualitysaddles.com/
And the one before that was bought at a local shore but came from here:
For odds and ends, I usually go to a local feed store or saddle store.
Edited to add: Given that I got my first western tack in 1965 and first English tack in maybe 1968 and have been in continuous accumulation mode since then, happily I don’t need to buy stuff very often! My favorite western headstall was made for me by my uncle. The aforementioned bosals were needed because 1) the bosal from 1966 is really pretty fully depreciated, 2) the 14.2h mare and the 16h gelding require different bosal sizes.
