1) How much is too much? --- I don't believe that there is a "too much".
2) To those with so much...Why? What's your rationale? ---I have many different moods and musical interests that are filled from listening. Classical is good in the morning or while working, and I listen to something different every day. Energetic jazz is nice in the afternoon, while quiet jazz works well at night. I like rock in the afternoon and early evening. Some evenings Diana Krall's Girl in the Other Room works well, but on other evenings I might want to listen to her Live in Paris CD. Pat Methany has some stuff that is inspiring to do work to, while some of his other cds is great before bed. Arvo Part's Stabat Mater is an excellent late night listen as well. I'm listening to Trinity Session (Cowboy Junkies) now - I may be in the mood for something completely different later and its nice to have a big choice. Some of Joni Mitchel's cds bring back memories of long lost loves. Santana, Moody Blues, King Crimson, and Pink Floyd bring back memories of my youth, and different cds relate to various points in time. I don't like some artists at certain times, but love them at other times. This is just touching on the "rationale" for having a lot of different cds and albums.
My point is that music adds to the fullness of my life, and enjoyment of many different kinds of music and variations on a theme expand that fullness. Besides, it's a fun hobby.
3) Are you crazy? --- No. (see above)
By the way, it's not a pissing contest, rather you should think of the sharing in this forum as a way to expand what you know about music and your choices. I've purchased some of the cds mentioned on several threads, and these have been outstanding and have become favorites.
John