What is the best place to buy tubes?

One thing I will say for Tubeworld ... tube descriptions and sonic characterizations are absolutely spot on, in my experience. Prices may be a bit higher than some, but products are exactly as described - Brendan knows his tubes. He and Andy Bowman at VTS are two of the very best.

Brandon at TubeWorld is extremely knowledgeable and stands behind his product with a money back guarantee.

So does Brent Jesse at http://www.audiotubes.com/.

As does Dennis Boyle at Chimera Labs who does not have as wide a stock but can often hook you up with great tubes at lower prices. Great guy to deal with.
http://home.att.net/~chimeraone/tubesaleslist.html

With all three guys the knowledge and advice is top notch, product is great and packing and shipping are fast.

Newbee -
Don't mean to beat up on the Tube Store if it's the manufacturer's quality issue. Also, just to be clear... the expected life/hrs they cited for the power tubes was well over 1000. When writing last night I couldn't remember the exact number so I just wrote >1000. It might have been in the range of 1200 or 1500 hrs. In any case, I expect they were being conservative though, as you can see, 2 JJ Tesla KT88s never made it nearly that far.

I did buy Ei Elite 12AX7s and NOS Mullard 12AT7s from them and those are still working just fine.

The Tube Store order fulfillment service has been great though I was not impressed with their matching service.

I didn't really appreciated that a tube failing suddenly could cause damage beyond a blown fuse. Thanks for the warning.

I have had great experiences buying from Jim McShane and Brendan at Tube World. Both are highly reputable sellers who know tubes.

www.tubemonger.com is my recommendation. Maybe not the source for the overpriced, exceedingly rare, overrated, name-dropping tubes; but, if you like reasonably priced, mighty fine tubes, check it out.