Linda,
Another great dining question, thanks!
So I think probably the best, classic steak would be at
Shula's, in the Dolphin Resort. It is a very old-school place, but their steaks are as good as they are expensive.
But in the realm of more realistically priced meals, I actually have two recommendations, and one will not be what you expect. The first is the
Yachtsman Steakhouse, over at the Yacht Club Resort. The quality has risen steadily for some time now, and they do a great job. The second is not Le Cellier, as you might assume. Instead I would send you to
Todd English's bluezoo, also at the Dolphin. Famed more for their seafood, this elegant and modern establishment does right by a steak!
All of these are in the Epcot resort area, and I would suggest Shula's or Yachtsman as your primary options, depending on your budget. My fireworks suggestion is predicated on the assumption you have park hoppers, and can go into Epcot afterwards for IllumiNations (which is the best fireworks show in the WORLD!). But if you cannot, consider watching from the Atlantic Dance Hall side of the BoardWalk, which gives a good view of the fireworks, if not the rest of the show effects on the World Showcase lagoon.
Finally, dinner show. No contest. No debate.
Hoop Dee Doo Review. Best show. Best food. Best experience. Just be sure to be in Category 1 or 2, with 1 if at all possible. That really improves the experience.
Have a magical (and delicious) vacation!