Edit: Root has closed since the writing of this post. Another vegan restaurant has opened in its place, but I have not yet been there.
Root is an all-vegan restaurant in Allston, a Boston neighborhood that is very close to my heart (and used to be close to my home, when I first moved out to Boston). It had big shoes to fill when it opened: its location was previously home to Peace o'Pie and before that, to TJ Scallywaggles, both vegan pizza places that almost all of us Boston vegans were sorry to see go.
Root has healthy, surprisingly inexpensive meals with a cafe feel. Kevin and I have been for dinner twice and brunch once. Dinner there was great!
While we were underwhelmed by the brunch (not a lot of flavor in the tofu scramble or the breakfast burrito), we'd be willing to try again, considering how good (and enormous) the pancakes looked.
A couple notes: for lunches/dinners, you order at the counter and choose your own seat, but brunch is a be-seated-and-waited-on affair. Also, Root doesn't offer desserts, but is conveniently located two doors down from Fomu, Boston's vegan ice cream shop. (The two businesses even share a bathroom.) If you don't want something as upscale as True Bistro, but want something a little less dingy than Grasshopper, I strongly recommend Root.