I'd really hate to see you with a hot back!! I know that is the worst! But, unless you are take a taxi from the airport to your hotel and leave your luggage there and don't plan to do any train or bus traveling, then I suggest the backpack. You can always leave it in your hotel, guesthouse, or hostel while you walk around the city, just make sure your valuables are in a safe place. Where in India are you planning to go?