Hi Trader,
FWIW, I have tried many tube amps and a few SS amps with my Klipsch speakers. Of the tube amps, one of my favorites is the 6BQ5, I've owned 2 6BQ5 based amps, one single ended and one push pull.
I also really like the KT66 type tube, I have a pair of KT66 monoblock amps that I have been listening to for the last few weeks, they are my newest amps and I am currently on the lookout for a quad of 350B tubes to try in the amps as they are supposed to be excellent.
My favorite tube is the 2A3 though, I have had two different designs of 2A3 SET monoblocks and they are my favorite. I would love to hear a pair of 2A3 PP amps also, but I'll always own a pair of 2A3 SET amps.
As always, YMMV, but these are my favorites at this point in time.