I think your goal is perfectly achievable using primarily SS or tube gears. You can either go branded or DIY. Just remember to make sure that the amplifier can drive your speakers well eg amplifier output power >> power rating of speakers.
Based on my experience and opinion, training your ears is the first thing to do. Personally, I would go for sound that is as close to what an instrument or how a person sounds in actual. The reason I say so is because descriptions vary from person to person and is very difficult to accurately say that two people have the same reference. Based on one persons sound reference, what the other one hears may not be so good. This is the reason I listen over and over to what the real piano or instrument sounds. I also listen to how real people sing. It is only after I have "memorized" these sounds that I compare vs what the audio set-up sounds. Added 9/7/2010 11:39am, note: I don't memorize electronic instruments
For me, what is the point of selecting an amplifier whether SS or tubes if its output is not close to the real instrument or the real voice? Due to this, I believe that it is only after your ears are trained are you able to make an informed decision which to select.