Our must do's over the years have evolved.
Ohana dinner used to be one of them. Don't get me wrong, we still like it, and do on occasion. It used to scream Disney so much so that it was our go to at start of every trip. We tended to not do a park on arrival, so getting in resort, unpacking, maybe grocery shopping didn't exactly set the tone for a WDW trip. But Ohana, which is special and unique in itself, watching the fireworks, etc. really did it for us.
50s PTC has ben a must do for us since our 1st visit in 1999, sometimes we even go twice on a 2 week trip. In fact, back in the day we may have eat at Ohana twice. I think we have missed 50s on only 1 trip in all these yrs. The food is very good, not fancy, but they do a very good job at making comfort food a step above your standard restaurant comfort food. The atmosphere and the antics all envelope the experience. And you have to save room for a PB&J milkshake!
San Angel Inn is our other go to. I think the only time we didn't eat there was in 99. DW loves Mexican food, and when we 1st started going to SAI, it was more in line with Tex Mex, which was what we were used too. But time has changed that, it is now more authentic than ever. They still have a couple dishes that your local tex mex may serve, but they don't stick to that as tried and true. Food is tasty, atmosphere IMO is tops on property(Be Our Guest now surpasses this very obvious reasons)and you don't feel rushed.