My personal favorites that fall into the 'Signature dining' category are Jiko, Tiffin's, Topolino's, and Monsieur Paul.
Some that are rated 'signature' are restaurants I like, but I don't think of them as signature - Le Cellier, Paddlefish, Morimoto, and Boathouse - I think the food is pretty good at all of those, but in my mind they aren't what I'd consider signature.