Should I buy a Class A Amp.

the only way I would go class A is if you need an extra room heater. 

I am no rocket scientist here, but my suggestion would be fairly high-power A/B tube amps, 100 WPC, aided by a s/s Class D amp in each of the bottom end or sub-woofs, rolling off at about 100 Hz.. The Class Ds take all the heavy lifting away from the toobs, which can run quietly, coolly, and never leave Class A and can be run at fairly low bias. I defy anyone who says you need to run Class A all the way down to 30 Hz. All in, I'm only pulling about 6.8 amps from the wall. And that's only when I'm entertaining the entire neighbourhood. By all means, By all means, dedicate a circuit breaker of 20 amps and a manual-reset GFCI. I run a pair of Tylers at 4 ohms and have never blown a 3 amp fuse. Never had better sound, either.

Could it be said that Class A amps, like Pass for example, play better on certain types of music? Better classical than rock, for instance?

As mentioned earlier, no.

The idea that an amp can be better at one form of music as opposed to another is one of the bigger audio myths out there.

Could it be said that Class A amps, like Pass for example, play better on certain types of music? Better classical than rock, for instance?

Actually, it was I who asked this question, and I had not ever heard this said before, myth or otherwise.

Fact is, with my Pass XA30.5, that is exactly the impression I get. Better on some types of music than others. Relatively speaking.

atmasphere +1     Besides the amp, don't forget the speakers - the cabling - the power delivery - the room - etal - play a significant role in how the music comes out.  If one type of music sounds better than another, any number of variables can affect that perception.