If NOS pre or power tubes became unavailable altogether, what new tubes would you buy?

@enginedr1960I I think the only thing Raul gets me thinking is that he's a poseur: His strong opinions are not backed by any experiences he cares to share. There is no "one-size-fits-all" perfect signal path out there, or we'd all have one and there would be no need for discussion or chat rooms. The very subjective nature of the audio experience is what leads to such a multitude of opinion.

Everything distorts, from your gear to the room to the shape of your ear to the engineers and mics. I believe well-designed tube gear distorts best to my liking; with the close exception of a well cared-for S/S Bedini, it's preferable to SS distortion.
As to NOS v. modern issue, I've never had the pleasure of the Hammersmith KT-88s, but have had my run of antique NOS TS-6550s, Mullards, Brimars, Philips and the like, and the modern stuff from eastern Europe and Russia.
I believe the Chinese have gained the upper hand in sound quality for KT-88 type tubes if you stick with PSVane or ShuGuang. Both have factories in Changsha. My favourite of that lot is PSVane's top-end Mk II Treasure series. As for signal Tubes, PSV's top-end CV-181s will blow the skirts off any 6SN7 tube, NOS or otherwise, I have ever heard. But they're big bastards, almost as large as output tubes. so that's a consideration. 

Dear @rauliruegas
Disregarding our differences on tube v. s/s, and assuming no-one has built the "perfect" anything linking source to ear, I'd ask your opinion on what you regard as the closest to perfect you've heard, irregardless of price, and same question for one on a budget of, say, <$20,000 (give or take). Thanking you in advance,
deepee99

@lewm,
Thanks for clarifying that not all 6SN7 *types* are identical. I was merely trying to assure him that he wouldn't be applying plate voltage to the grids or heaters. Electrical variations (as I mentioned) do vary from tube to tube. Of all the 6SN7 types there's only one to be leery of and that was a mil-spec RCA VT-231 that pulls significantly higher filament current and could stress the x-former tap. 
Yep, it's important to find the tube's idea point on the curve, which depends on your circuitry. I (and the design used in VTA/Tubes-4-Hi-Fi gear like about 45% for the 6SN7s I use but it's not a magic number. I sure wouldn't go much above 65-70% for such a low Mu tube.
If John Bedini could build the "near perfect sounding" amp out of sand components 30 years ago, I am sure there are ss pre-amps and pwr amps out there I'd like better than my tube lash-up. But as you say, most of the new stuff has crap fail-safe circuitry and cheap parts. Even on the tube side a lot of very expensive production gear uses junk. Why McIntosh went with the EH tubes in their driver section I'll never understand, when for a few bucks more . . .
As to s/s vs. tubes, that horse has been beaten to death. Whether tubes or s/s, the sound is going to be far more flavoured by preamp components and the amp's driver section than the honkin' amp, at least according to the all-knowing myself :-), and might be worthy of a thread if there ain't one.
Cheerio,
-d-

@rauliruegas 
If you can't identify at least one piece of gear you believe is better than whatever other piece of gear (or better yet, the entire signal path) you've heard, as I have asked you for, then I suggest your opinion reflects the depth of your experience. C'mon, give it a try. I won't flame you. I just want to know what experiences you are basing your opinions on. Perhaps I will learn something.

I have had excellent success with two tube-dealers.
McShane Designs for new, mostly Russian and European, knock-offs. Jim really puts the new tubes through a torture test before he ships. He also has a smattering of NOS tubes, but for Russian GL KT-88s, hard to beat.
For NOS, Andy Bowman at Vintage Tube Services is also very decent.

For crying out loud, @rauliruegas all the poor guy asked for was advice on tube availability. It’s like he walked into the hardware store looking for a couple of lockwashers and you’re trying to sell him a boat. Get off your high horse!