I completely disagree with Elizabeth!
You should immediately go out and buy as many expensive NOS tubes as you can find. (And, at least one of each type, and better yet, two, as you'll instantly have a backup set for the ones that you like the best!) This will allow you endless fun listening to the same music, over and over and over again, comparing the different tubes! Nothing says "Confirmed Audiophile" like a guy with hundreds of spare tubes! Oh, and don't forget to buy a tube tester while you're at it! No TRUE Audiophile is without one!
Elizabeth, on the other hand, didn't want to buy any of the multitude of tubes I had for sale, (let alone the tube tester!), and instead, (foolishly I might add!), chose to spend her time listening, (and somehow, enjoying), her music, foregoing the pleasure of endlessly swapping out tubes, and exactly how each and every tube differs ever so slightly in its sonic attributes! (Silly girl!)
;-)