LOL!!!!! Stephen will grown on you if you give him the chance. You are not the 1st person I've heard that from. I was going bone fishing in Cozumel and had literally just hung up the phone with my guide on what flies they had been hitting that morning the day before my flight. I popped by Backwoods the was grabbing my last crazy charlie when Stephen announced that I had all the wrong flies and he stocked me up with a few more patterns. I will say I caught them on the crazy charlies and a the patterns he sent with me, so I gotta give credit where its due. I learn something every time I go in for sure. He did try and sell me a $50 pair of nippers last time though.........I hope I'm not turning into a peacock.

Also humbly submit Dirty Sally's in Ten Sleep, WY
More of a general store than a fly shop, but they sell flies.
Recomend the Strawberry Milkshake. For something stronger
head across the street to the Bighorn Bar. Look for the Sheriff's
car parked out front. He apparently offices there.....

Charlie's Fly Box - Arvada, Co : Dale mentioned this one already, but I was in the neighborhood and stopped by Friday. All I can say is WOW!!

I have never seen so much fly tying materials in one place before. The fly tying material selection in this store is incredible. They had colors and sizes of materials that I've never even seen listed in a catalog before and they had it on the shelf. This is definately a fly tyer's dream shop. (And their bank account's nightmare...)

If you are in the Denver area, this shop is worth a detour to visit. It is just a couple of blocks off of I-70.

http://www.charliesflyboxinc.com/

Here are two more...

Yellowstone Angler - Livingston MT
Best shop and guides for the Yellowstone
River and Park

Henry's Fork Anglers - Last Chance ID
Check with Mike Lawson for best advice,
flies and guides for fishing both upper
and lower Henry's Fork of the Snake