I've put a whole lot of food in my mouth to come up with a top 5.
I've had experiences though, that I can put out there.
The steak in Firenze. Holy sheep shit. To hell with the pasta. Give me the steak.
The progression at Topolobampo in Chicago. Never had better Mexican food than that.
The ribs at Twin Anchors in Chicago. There's nothing like that joint. Just go if you can.
Tapas in Barcelona. Also, dinner at Set Portes there. Pretty amazing stuff.
The restaurant at Shutters in Santa Monica. Holy crap, the sunset was awesome and the food even better.
Le Francais in Wheeling, IL. RIP.
There are a whole lot more.