I've been to a lot of these. My favorite on the list is Per Se (19) in NY, but not because of the food as much as my company.
However, #5 sticks out in my mind for the way they treat their dinner guest. It is located in Disney at the Grand Floridian Hotel. When we made our dinner reservation, they had our names printed on our own personalized menus. I really felt like a Disney Princess there.
I find Trip Adviser overall to be very useful. No review site is perfect, but with a little care and reading the reviews, not just looking at the number of starts, I have been lead right far more often than wrong by it.
The actual top listing obviously changes, but at various times I went to the #1 restaurants in Santa Fe (an excellent Indian restaurant that is currently in the top 5, but not #1). The #1 there is now a chocolate restaurant--excellent but WAY over priced. Very good African restaurant in Vancouver, in the top handful, but the highest rated of it's genera. I have never been to a top-10 tripadvisor restaurant that was bad (or even average), but some are definitely overly pretentious/priced.
I was very surprised Bobby Flay's restaurant in Las Vegas was rated as low as it was. I have been there a number of times and it was outstanding bordering on god-like most the time.