I was in India in June for business, and loved it even more than I expected. You've already got a great list of must-see places... just do it!

Hint: at the Taj Mahal, tip a wizened local a couple of bucks to show you the smaller entrance gate which is around to the right of the mobbed main entrance, and save up to an hour.

Of course get travel insurance. There's nothing wrong with the best of Indian healthcare (look at all the Europeans who go for cut-rate procedures) but I think you'd want fly-out options in an emergency..

And think twice about street food, when you're in a place where awesome restaurant food is so cheap and accessible...