My AA is determined by my personal preferences, and not external factors, such as have been mentioned here. I use my age, and risk tolerance as well as projected income needs.
At 69 y/o, I am at about 60% stocks, and 20% bonds and cash. All non cash investments are in low cost mutual funds and ETF's. I note the end of each day results, then do something else.
I can financially handle a "great depression" style downturn without having to adjust my lifestyle. I suppose my heirs would be less than happy. :)