This might be a tough one, since by definition a chain is bad and to be avoided. And even if a really good restaurant tries to become a chain, it rarely works. Think Legal Seafood here.
But there are some good ones that have a high standard of service and quality.
The Palm is a favorite and I believe that each of them are fantastic restaurants.
http://www.thepalm.com/
Mortons can usually be counted on for great food and service.
http://www.mortons.com/website/index.html
I'm sure there must be one or two others out there?