It's certainly good to do some research and get some kind of general grasp of the subject on paper. But your best bet for actually starting to associate sounds or a general sonic signature, with those words on paper, is to start listening to various topologies. The options there are to seek out audiophiles in your area who are willing to have you come for a listen. Go to local dealers. Go to the larger audio shows. Buy and sell used and actually implement the amps you are interested in into your own system, your own room, and with your own music. The latter will require more patience, effort and investment, but will probably be most rewarding. The amp-speaker interface being rather critical makes the latter task all the more challenging (buying one tube amp after another and just sticking in with your existing speakers is probably a waste of time - if you are looking for a tube amp to go with the speakers you already have you may want to start there).
My preferences? Well, first of all, and I hope anyone realizes this, my preferences are not your preferences. Even if you had a thousand audiophiles provide this input and averaged the totals you the results would be utterly meaningless in determining your own preferences. That said, and FWIW, I've loved SET amps for many years combined with horn speakers, but their magic often has a limited range in terms of music that sounds great with them, in my experience. Ralph's OTL amps are great, and much more versatile than SET while sharing some very similar qualities. There have been some PP amps I've enjoyed. Not many SS amps that I've liked over the years, but I've currently found one that has really wowed me enough to own it and sell my SET amps of 6 years. I've also had a pair of class D amps I thought were very enjoyable. If I had to make some sweeping generalization about my own preferences I'd say there have been more things about tube amps that I've liked than transistor amps, but the few SS amps that I have liked are very engaging to listen to. They've been few and far between. I love the seductive quality of SET and for me the colorations don't bother me, and the music I like most is not among that which really challenges the low powered SET amps I had.
It may help in your queries if you try to determine what qualities you enjoy most in a system (linearity? warmth? accuracy? slam? dynamics? soundstaging? etc, etc). Additionally perhaps what kinds of music you prefer (though many would argue that a good amp/system should be able to present all kinds with equally good results). How large is your room. How do you listen mostly?
Hope that helps in some way. YMMV, as always, as far as personal preferences.