Nitro X.

If you want to do the usual tourist thing, I would recommend the North West (Rajasthan, Delhi and Uttar Pradesh for the Taj but more so Fatehpur Sikri). There's history all over India but the weather is better in this region during the winter months. Unfortunately, it's the peak tourist time for India, so be sure to book your accomodations as early as possible.

It would help if you could tell us the number of days you intend spending here.

Rustam