King - this is going to be a long thread. I have found each to have its merit. D2 will probably come in high on the list. I do not use it for two reasons: it is expensive (and I am not consistently good enough with my grinds yet to afford to waste a piece)and I do not have the equipment to heat treat it. Personally, I like 5160. When properly heat treated it makes a tremendous knife. You get an inexpensive gas forge, oil quench it and temper it in your kitchen oven (if your wife approves!) It is very inexpensive compared to some of the others like O-1, A-2 or D-2. Many of the makers here like 1095 which is also a good steel and inexpensive. You will get a wide variety of opinions in answer to your question. I would not argue with any of them because I could make a good argument for each.
Fox