This list of 21 vegetarian/vegan restaurants all over America from Thrillist is wonderful. Some fabulous names on here, ones that I have always wanted to visit.
Veggie Galaxy in Cambridge, MA is by far one of the finest vegetarian diners I have been to. Red Lentil in a suburb of Boston is another fabulous restaurant. Some of the best Samosas I have had outside of India, was in this restaurant. Both of these are featured in an article I did for the Boston Globe Magazine titled How To Be A New England Vegetarian In Winter.
Now I have to book some tickets to visit those that I have not been to.
The full list of restaurants is here.
The Worldly Vegetarian 