I've would have a drink with his personal cleaning lady when she was done for theday, and drank more than one with Tony himself late into the night at Kareoke in his personal Airstream park. Many of my friends worked in all departments at Zappos, as well.
When the drinks were mostly finished, and the clock was past 3am, the #1 rumor would be of his drug use. At first I thought it was standard rumors due to his laid back nature and stature (and maybe confated with the fact that he smoked weed legally.)
However, after an interpersonal issue, one of the people with access to his private life pulled me aside and showed me a series of photos he had taken in Tony's place prior to anyone cleaning it up.
Let's just say Ketamine and Nitrous are weak comparitively to what I saw, and there was a reason he could be "on it" for 3/4 of a day and then immediatly sleep. I don't know how to say it without speaking too ill of the dead, but I think you get the idea.
PPS, Google the Downtown Vegas Suicides for a true, fun, short read.