I think Holy Grail means something different to different people. Some collect bottles because they are collectors and may not open them unless they have an extra. Some open everything. Some want to taste history, e.g., I was curious about Old Taylor and Grandad in the 70's when National Distillers made them partly because I remember them being very good then. So I got some and tried them. I do think they were better than the equivalents today but primarily I was interested to try them to see if they matched what I remembered from that time. Some people seek prized bottles said to be very good and rare - Hirsch 16 and 20 are both. I agree with Chuck that rarely though will there be a "eureka" taste and that most older bourbons are not better just because they are older. The reason in my view bourbon flavors don't dramatically change or vary is because bourbon is legally defined (as to how it is made): even changes over time in production methods, yeasts, etc. can't really alter its fundamental approach. As good as the new BT Experimental bottlings may be, it's still bourbon. The same for S-W bourbon from the era when its distilling-out proofs were lower. I've had some fine tastes (e.g. an Old Weller from the 60's) but it is still bourbon whiskey. I feel I've vatted up samples as good as the best oldies I've tasted. So, I believe everyone has their own definition of Holy Grail. But just to "answer the question", I'd say that the Stagg Fall '05 bottle (which I've now tasted from a few times, it is a friend's bottle) is or is very close to the best bourbon I ever had and if I saw a bottle on the shelf I'd buy it.