This thread refers to the original restaurants that offered vegetarian food and which closed, not the reincarnated version of them, such as the new Samosa's or the new Govinda's.
Here is my list of vegetarian restaurants that once operated in the southeastern Pennsylvania area, but closed for various reasons ...
Govinda's (originally on the 500/600 block of South Street in Philadelphia. Great selection of Indian food in its buffet (priced per lb) with the unique flavor/spicing that the Hare Krishnas are known for in their cooking. The restaurant also had western type foods in the buffet like whole wheat pizza. This restaurant didn't necessarily have the best quality of food, but the flavor in the spice mixture made it unique and well worth visiting. The food always left a very nice aftertaste in one's mouth and spirit. (The new Govinda's does more international upscale vegetarian fare. The original Govinda's fare and ambience was closer to giving you a taste of the Hare Krishna thing, with food closer to what's served in India than in an upscale western vegetarian restaurant.) A fire in the kitchen ended this restaurant's existence in this location.
The vegetarian restaurant located on the second floor of a building located at the corner of Broad and Walnut in Center City, Philadelphia. Entrance from a very narrow walkway up a flight of stairs to the second floor opening up to a very large room, sectioned off. I think the place also had a small art gallery. This restaurant had a very nice selection of vegetarian foods from different parts of the world as well as your mainstream vegetarian foods - consisting of tempeh, tofu, and miso flavored dishes.
I can't recall the name of this place. I remember it as being one of vegetarians' favorites and one of the original vegetarian only type restaurants. I think this restaurant predated Essene's veg restaurant.
Horizon's in Willow Grove. Now relocated in the South Street area and even more upscale vegetarian fare from their creative upscale vegetarian fare in Willow Grove.
The vegetarian restaurant that operated next to Garland of Letters on south street in the 1980's. Real cool ambience, southwestern decor, neat board behind the serving area that had the day's special chalked in different colors on the board. Mostly vegetarian sandwiches. A very comfortable place and oasis in Philadelphia. Gave you the feeling of being in the southwest eating healthy comfort food. Reasonably priced and down to earth place. Can't recall the name of this small restaurant. I'm not sure, but I think when this place closed, Govinda's took over.
Only Nacheryl. Located in the Chesterbrook Shopping Center. Very busy at lunchtime. The best salads and freshly made dressings. Delicious variety of sprouts. Extremely fresh food. Creative dishes, including variations on veggie burgers, freshly made juices - many varieties of juices. Combination of raw food dishes as well as cooked vegetarian foods from different culinary traditions. Romantic ambience for dinner. When Whole Foods (then Fresh Foods) opened up its market in nearby Devon, the days for the restaurant and the health food store that the restaurant was located in were numbered, and the store and restaurant eventually closed.
Samosa's. Located on Walnut St. in Philadelphia. Not the best vegetarian Indian food, but it served as an accessible and inexpensive place to get vegetarian food from a buffet.
As far as the Philadelphia metropolitan area goes, these are the restaurants that I remember that offered vegetarian food, and that were enjoyable to eat at, each for various reasons.
Other Chowhounders may be able to recall other vegetarian restaurants that once were, but are no longer, that are worth recalling. I did not include any vegetarian restaurants in the NJ or DE area since those were not areas that I explored. My list was not meant to slight those areas, but rather reflects those places that I was familiar with.
It would be fun to read of Chowhounder's experience with any of the places I have mentioned. I'd bet that very few people knew of Only Nacheryl in the Chesterbrook Shopping Center. Everyone raved about the quality of its salads and the freshness of its foods The one major negative is that meals sometimes took very long periods of time to be made and be served. This was not a place one was able to get in and out of quickly. Govinda's was a great place to overhear fascinating conversations from nearby patrons on Hindu scriptures and other faiths. All these restaurants served as "training wheels" for me as I began to explore vegetarian fare and cooking it myself. Thank you all!