My best dealings have been with individuals, private sales. I've had many dealings with gun businesses though, I know I'll get some heat on this one, but some of my best dealings were with Cabelas back when they kept a ginormous selection of good quality guns.
As far as the small shops go, Niles Wheeler was very good to deal with.
Back in the day Duncan at Hill rod and gun was good, Charlie is a good guy too.
I've had some good dealings with Steve Barnett too, every time we made a deal he'd throw in a couple nice extras here and there.