Go read (hat tip to Jakob Nielsen).
Here is my take/addition to this article - people (chefs) just don't realize/know what they need, and they think that they have to sell or dress up their websites just like they do their food - and so they get sold on things by poor developers, or the developer just says yes to whatever the chef wants for fear of losing the job, etc. (and I bet that most chefs/restaurant owners are cheap when it comes to the web because they don't believe in it).
Anyway - there are basic simple concepts that must be followed, as always, no matter what the industry is and we talk about them all the time. Simple navigation, clean design, information quickly and easily. It isn't rocket science - there is no need to "tart" it up - especially in the increasingly mobile world.
This is all a restaurant website needs:
Hours, Location (and a map with directions or directions available via Google), contact phone and email, sample menu (no prices!), sample wine list, and a photo or two.
You want to go crazy and plan to update the site all the time? Add a current menu with prices, current wine list with prices, and a photo album. Perhaps a link to reviews on Yelp and TripAdvisor. Maybe a sign up form for a newsletter (but only if you are going to really send a newsletter).
Insanity levels would include a reservation system via form of some kind.
Otherwise, use blogger or Facebook to add current menu items, announce specials, news, etc. Anything else is really overkill, and not anything someone who wants to eat your food needs.