Thanks for all of the thoughtful insights. It seems a better choice to save some dough and plan on getting a new amp instead of spending $1000 on tubes. I've been chatting with Fritz of Fritz Speakers about a pair of Carbon 7 SE Mk 2s. If the deal goes through I'll lick my financial wounds for a while and use them as a basis to select a new amp.
Musical tastes certainly evolve and refine over time. Twenty years ago I was listening to lots of organ and symphonies, primarily on CD. Now, it's leaning toward quartets and early instrumental and vocal music, mostly on vinyl. The Slayer CDs rarely make an appearance in the home system.