we ate at rose and crown in sept. and had a delicious veggie pot pie. We also had the potato and leek soup.
at san angel in in epcot they have a special vegetarian menu, the combination plate is really good. The chips and salsa aren't as good.
We also ate in Italy in epcot and it was good but it has since changed so i can't say what is on the menu now.
In the magic kingdom there is a delicious sandwich at columbia harbor house called the lighthouse sandwich. They also have vegetarian chili which my boyfriend liked a lot. I would seriously never consider eating a veggie burger from mc donalds while at disney world! They have so much good food.
At Animal kingdom they turned the tusker house into a buffet so the only thing we found to eat was the pizza at pizzafari which wasn't bad, but considering it's the ANIMAL KINGDOM you'd think they'd have more vegetarian stuff. I had always liked the veggie sandwiches they had at tusker house before

I have read that the new tusker house does have a vegetarian section to choose from.
At MGM they have a stuffed pepper at Prime Time Cafe, and a great eggplant dish at mama melrose. Hollywood and vine is a buffet so there are a number of veggie options like mashed potatoes, mac and cheese, salads, and some other stuff but it's just the generic type of stuff. They also have a tebbouleh wrap that I've had at the commissary and i liked it, though other people on the boards did not like it.
As for resort restaurants - pop century had a veggie flat bread sandwich that was really good.
Animal kingdom lodge has boma which has an array of vegetarian options, it's one of my favorites! They also have some stuff at the mara, a felafel sandwich, and my favorite butter nut squash soup.
port orleans french quarter has a vegetarian sandwich that's pretty good but last time they went a little heavy on the marinade. But still not bad considering.
Ohana at the Polynesian also has a vegetarian dish which is pretty good but not the best I've ever had. Their scalloped potatoes are really good though.
At the Grand Floridian the 1900 park fare is pretty good and it's so easy to get here from magic kingdom on the monorail! They have pasta, salads, all kinds of veggies, mashed sweet potatoes, and a strawberry soup that is so amazing, and just when you think it's over there is the MOST DELICIOUS BREAD PUDDING. mmm. My boyfriend liked this place a lot!
At down town disney: Earl of sandwich has a good Caprese sandwich, I would definitely recommend it to anyone. Wolf gang puck has a cheese quesidilla that is topped with a ranch type dressing and I liked that a lot, it was different. Rain forest cafe has a few different sandwiches that are decent for a vegetarian.
These are only the places I've been which means there is SO MUCH more to try out there. I would check out Allears.net for the menus if you want to see more, menus do change but there is pretty much ALWAYS a vegetarian option at each of the restaurants and many of the counter service places.
I hope this helps!
tricia.