It's an addiction, there is no end
Friends and family don't want the equipment quest to stop...I've collected so much stuff over the years that I have 4 different two channel setups scattered around the house, in addition to equipping parents, sis/broinlaw, and several friends. I don't think I've paid full retail for anything over the years, and I've kept to mainly mid-fi type stuff (amps: NAD, Adcom, Emotiva, Crown, Yamaha; speakers/subs: Miller & Kreissel, Def Tech, Klipsch, Mission, hot-rodded Onyx; a multitude of cd/dvd players sonyES, Yamaha, Tascam). Despite the seemingly endless flow of gear, it hasn't really been terribly expensive.
I figure as long as you're having fun and you have disposable funds available, there is no end to this hobby. And speaking of fun, one of my systems is a SET amp/high efficiency speaker, minimalistic setup, which may not be hi-fi according to some uptight slide-rule objectivists geeks that frequent this site, but it sure is fun to listen to! This system is the most engaging, the easiest to get completely lost in the music with. If I had to settle on one particular system and forego the others, this is the one I would choose, hands down, and I would be quite satisfied. To say the image is three dimensional is to do it a disservice; it's huge and engrossing, like 1080p for your ears. This system is flat out fun. In fact, this system gets far more milage than any of the others right now, so maybe this is the spot where 'enough' has finally occurred for me.