Nice post, Edgecrusher. I've always been a fan of tube history and tone too, and miss some of the tube expos that used to exist....audiophile and guitar amp related trade shows. I was usually the youngest guy there, it seemed. Luckily, I learned a lot from some of the older tube fanatics I met, like Myles Rose, Aspen Pitman, and oldsters who worked for GE.
All I can suggest to guitar players who are into tone is to try and own one prime example of every classic amp in their lifetime, and get them all running their best with nice tubes. You'll learn a lot by owning a Vox, Fender Blackface, Fender Tweed, Marshall Plexi, JCM 800, Mesa Rectifier, Dr. Z Rt. 66, and any other classic example of a tube type.
Youtube clips will give you a rough idea, but actually owning some classic amp models will teach you the sound, the feel, the dynamic range, and all the nuances you can't get from second hand info.