Where do you guys buy tubes?

Great suggestions above, pretty well covering the gamut of reputable sellers.  Jim McShane is the best of the best in my view.  There are lots of good prices from tube sellers on e-bay, but it is very easy to get burned there.  It is hard to separate the wheat from the chaff with some of these sellers.  

I have purchased from  Andy Bouwman at Vintage Tube Services, Jim McShane and Tube Depot.  All three provided excellent service.  
That said, I just picked up 4 Amperex 7308s from a seller on ebay (Elderly Electronics in OK) and both the seller and the tubes were excellent.

I tried buying from Upscale.....four phone calls, I gave them my number four times...their salesmen were apparently too busy to help me out.... no return call after four attempts is pretty sad so unfortunately I can't recommend them.  

I can buy anywhere as long as the seller guarantee it's tubes on test results on what tester but not on emission test.Pay attention for matched transconductance and  plate current.Double triode like 12A( )7,6sn7,ecc88 etc.,they must be matched at least 10% or tighter triode-triode for Gm & Ip,non-microphonic,very low noise and no hum.