You could do worse than the White Dog, over near Penn. They're very local produce, organic, feel-good, and the food's tasty as well. http://www.whitedog.com/
Friends swear by the brunch at Monk's (http://www.monkscafe.com) in Center City but I've never been and for all I know all of their entrees are made with ground veal. So I'd call ahead.
Pennsylvania Wine discussion list - groups.google.com/group/PAWineTalk/
Thanks for the tip. We gave Farmicia a try last Saturday. It was fair and reasonably priced. The best parts were where they combined fruit and herbs -- we especially enjoyed their peach-herb elixir, which is a reduced syrup of fruit and herbs, that comes into a shot glass and can be poured into club soda. They have several, but we only got to try the one. We finished with a blood-orange and thyme sorbet, which was unusual and delicious.
On the other hand, my frittata was bland. My mother-in-law ordered Tofu & Italian Spiced Soy Sausage Scramble. I had expected a tofu scramble, which is soft tofu gently cooked with a consistency similar to scrambled eggs, but instead she received squares of sauteed tofu. She liked the soy sausage, and mentioned that it had more flavor than the brand they use at home. To my tastes, the dish tasted like the kind of stereotypical vegetarian cuisine that turns people off vegetarianism.
My wife's brioche french toast as good, particularly eggy, but I like it that way. My father-in-law had basic scrambled eggs, and they were handled well.
I had a bloody mary that was wonderfully sharp. On balance, the meal was pleasing, and reasonably, though not cheaply, priced at $55 plus tip for 4 people including my bloody mary.
Another good brunch spot for vegetarians is Azure:
Also a good lunch / dinner spot -- they do a great job with their seitan dishes ('steak tips'). Good for carnivores and veg's alike.
I've been to Farmacia twice and I wasn't all that impressed with the food, and was even less impressed with the service. Which is a shame, because the concept is right up my alley...
I've also heard that Honey's in Northern Liberties is a good brunch spot for vegetarians, but I haven't been yet.