It depends what you consider the best. I consider the best is something that looks nice but also serves its purpose. There is such thing as over kill if there are to many gadgets because whats the point of all of them. I also am not to crazy about flash so i dont think any flash design would be the best.
P.S. Im currently working on a site which has a very nice clean design but, the design is not the best part of it. The backend is the best part. It uses and asp application to query multiple XML documents and then builds one XML document and applies a XSL stylesheet to it on the fly which makes the XSL transform and in turn generates the XML to be displayed. The advantage to this is that it is more flexible and easier to manage than static html pages but, it is faster than a conventional database driven site because the asp uses pure text streams to query the XML documents. Unlike a database driven site which uses a data stream from the database. A webserver can serve text much faster than it can serve data from a database.
there's sooo many that saying best is not fair. It's like saying "The best shoes are reebok k34 size 10s" or "the best food is applesauce"
There are a ton of really great ones, two very popular ones are http://www.whoswe.com/ http://www.estudio.com/
But I have seen many things on this here internet that have wowed me, and I wish I remebered the URLs... some really incredible stuff. Dam I wish I kept those links somewhere...