Indian is my favorite type of cuisine and so I've tried every place I can find. Haveli is so far my favorite Indian restaurant in the Madison area. I've only had the occasion to visit a couple of times but they have been consistently excellent on both occasions.
Both times it was for their lunch buffet and the selection was broad enough to allow me to try a lot of different things, the flavors were rich and well developed, the wait staff attentive but not in your face. All in all it was my ideal lunch experience.
My wife also enjoyed the fact that they didn't overdo it on the heat of the spices so that she could also try everything.
Their cost were on the low end of average for buffets in the area, as well, which certainly doesn't hurt.
I try not to eat at buffets often, when I do they are Indian, and for the foreseeable future all my visits are saved for these guys.