Gokul is probably my favourite Indian vegetarian restaurant in Singapore. It's got a very handy two locations (one in the Fortune Centre and one in Little India), an excellent menu, and is fast service and I love it.
The menu has a variety of bread sets, curry dishes, and local foods like char kway teow and chicken rice. They also have an excellently spicy murtabak and a good dosa, and they don't mind when one of your group brings in a frozen vegan cheezecake to eat for dessert.
The menu at the Fortune Centre location isn't as extensive as the Little India location, but I go to it more often due to its convenient location, so you can tell that I don't mind.
Gokul Vegetarian Restaurant
19 Upper Dickson Road
190 Middle Road
Get there on the MRT, mostly. There's a step to enter the Little India location, and ordering happens at the table; at Fortune Centre, ordering happens at a high counter. Cards are accepted. There's an awkward toilet in the Little India Building; Fortune Centre has a toilet down a twisty hallway.