The best way to design an audio system.

Well, because I am not an old timer I hesitated, but after learning nothing new here, maybe I am on the other side for this topic. To choose a system, I would try to audition as many types of systems I could, like esl, planar, dynamic, high-efficiency, headphones, turntable, CDP). Second, I would think about and be extremely honest w/ myself about practical concerns, like money, S.O., amount of self-energy I would like to put in to my system(some systems need more energy than others), what sort of buying I am comfortable with(e.g. dealer, used, internet). Third, discover what speakers I enjoy from the system type, within the relevant practical concerns that have a tonal balance that suits my room. From there pick the component from the type(speakers, amps, preamps, source, cables)that has the fewest sonically reasonable options. Usually that is the amp, because whatever speaker you choose will only be happy with a limited number of amps. Last, like others have said, room treatment is very beneficial. There are a lot of ways to put a system together, and the philosophy is whatever works for you. Better answers come from more specific questions.