I haven't kept up with who is considered to make the "best" tubes these days, but Mesa have always sounded great in my Marks and never let me down, and have entered the Stupid price realm in recent years.......
For me, it’s tubes as well..
I’m not at Psychodaves level, but I’ve been saving them for years. I did some work for an old guy who was a radio and tv repairman for years and swapped a repair for an assortment of preamp tubes he had that were all new NOS stuff in the original boxes, probably close to 30 Amperex, GE, RCA, Mullard and a few others. I put them in a foam padded case to keep them safe from outside influences as a lot of the boxes were in bad shape from age.