In the real world, better the speaker, better the quality...
For example, i happily drive a 20watt (generic) satellite speaker from a 5.1 setup and avoid all the little cheapy speakers, those speakers are generally heaps better sounding regardless of your driver it's just a thought, I use a cheap amplifier with a decent speaker rather than a cheap speaker (they sound tinny)
But you know if you don't mind the power loss you can build a Class A? (the crappiest of all of them) using a half decent power transistor and 3 resistors practically but is a waste, it's better to amplify it in stages and give a feed back , but literally a tip31 a voltage divider gives a killer amplifier circuit if you don't mind wasting the power that is....