Vegetarian in Midtown?
My two favorite vegetarian restaurants in all of NYC are in midtown Manhattan.
Mavalli Palace, 46 E. 29 St. --Southern Indian
Hangawi -- 12 E. 32 -- Korean
Neither is super cheap, and Hangawi can get a little pricey if you have one of the fixed-price dinners (which I recommend). Hangawi is a lovely restaurant, where you sit with your shoes off, and the service is lovely. Some of the root vegetables are unusual and bracing.
If you aren't familiar with Southern Indian, though, I'd try Mavalli first. It's reliable. Try the dosas, the cashew appetizer, any "wet" dish that suits your fancy, and the malakapodi, a great condiment.