Speakers first is a classical approach. It will work.
However, since you are not quite sure what you are looking for, you might first want to figure out whether you want tube amp, transistor or hybrid, or it doesn't really matter. Some speakers will sound good with any of them, some won't. Within this amp first approach I would listen to Vac Avatar and Vac Sigma to begin with, then Rogue tube and hybrid, then Accuphase.
NAD receiver won't give you a gateway into the high end audio.
However, since you are not quite sure what you are looking for, you might first want to figure out whether you want tube amp, transistor or hybrid, or it doesn't really matter. Some speakers will sound good with any of them, some won't. Within this amp first approach I would listen to Vac Avatar and Vac Sigma to begin with, then Rogue tube and hybrid, then Accuphase.
NAD receiver won't give you a gateway into the high end audio.