My regular favorite is Lagavulin 16-year. It is an Islay malt sent from Heaven. But as long as you've raise the Macallan flag, I have to admit that the finest, most perfect Scotch whiskey I have imbibed (and I've imbibed a lot of them) was a 25-year old Macallan than a dear friend of my family gave to my father. (I remember it was marked as having been bottled in 1966). He kept it in his bar, awaiting a special occasion, that alas, never came.
My father died before having the opportunity to share it. So in his stead, I took the inherited bottle and shared it with three of my friends on the occasion of our 25th college reunion. The first glass I offered as a toast to my father and imagined him looking on down, approvingly.