I have yet to see a transistor amp that can play bass as well as a good tube amp. They don't seem to go as deep or have as much impact as tubes. Of course, I am using a speaker that is tube friendly (and has 20Hz bandwidth).
I listen to all sorts of music. If you have a good amp and speaker, the type of music is really unimportant- it should play Wagner as well as Massive Attack, Bill Evans, or Fields of Nephilim. The idea that a speaker or amp is best at one type of music is really a myth. Both are processing a signal and don't really care what the signal is.
So if you are looking into tubes, the main thing is to have a revealing speaker with as much bandwidth as you can afford that is also **easy to drive**. Tube power is expensive so its usually best served if the speaker is moderate (91 db) to high (+99 db) efficiency, with an impedance of 8 ohms or more, particularly in the bass region. Otherwise if you go with lower efficiency *and/or* low impedance in the bass, it will be like running a Porsche with really cheap tires- you will never realize the amp's capability.