I think there's a real fine line there. I probably wouldn't appreciate music as much as I do if it weren't for pot, mesc, and acid. However, I found that, in retrospect, the downside of it was that they made intolerable situations in my life tolerable. Instead of changing them I put up with them. It wasn't until an unrelated medical condition forced me into sobriety that I had to face the fact that if certain things in my life didn't change I'd never be happy. It wasn't easy, but I did change them and haven't looked back since. While I still have a few beers now and then (and an occasional dalliance with Capt. Morgan) I haven't touched drugs in over 15 years now and, while I have fond memories of some of the experiences I have to accept the fact that trying to repeat them is incompatable with my current medical situation. They're not worth dying for.
They do open you to new perceptions. The goal of the shamans, however, was not to rely on the drugs for this, but to carry the experiences and perceptions into everyday life and to be able to 'see' them under a normal state of mind.
One side effect of sobriety, I've found, is memory. Some of my friends still get high at concerts. I find that they have to ask me for the details and the setlists afterwards 'cause they can't remember them! They remember having a good time, but they're not sure exactly why.
That's my 2 cents, anyway.