Most excellent thread and I am totally on board with your #1 pick. I love Morbid Angel and no matter what evolutions death metal goes through, those first three albums still set the bar for what it means to define a (sub)genre as far as I'm concerned. Trey is my favorite metal guitarist, putting last year's album aside, I still love even the lesser-received albums like Heretic and Gateways.
I was also at a total of four shows, from your list; the other two are your #1 and #2 picks
Maybe there were more that we had in common and those other ones just didn't make your own top 20. But I think we can agree that the four we shared all kicked ass front to back.