I'm a fan of the Bombay Grill (the original) in Baltimore, where I grew up, so I might be a tad biased.

Heritage India in Dupont Circle in DC is nice, as is the Bombay Club (though more for ambiance, location, and politico watching than the food, which is good just not great). I had Bay Leaf in Midtown Manhattan, and it was fantastic and innovative. hmm. Food Factory is nice, a bit of a hole in the wall, at least the one I went to with friends who studied at UMD- College Park.

Lahore Tikka in Toronto. It's been over 10 years but those kebabs and tikka....