Accomodation for any taste, ie for any budget. Honestly, living in the center is more expensive, but there are pros: you will be the first when museums are open, here it makes a sence, because of the large crowd of tourists in the queue, besides, you do not have to spend money on transportation. To rent a car, does not make any sense, you could not drive through even a couple of quarters, just get lost, not to mention parking, fully trust a taxi which is very democratic. In addition to the historic center, is necessary "as must" to walk on Istiklal Street, from Taksim Square to the Tunnel. Istiklal is probably the most beloved and crowded street in Istanbul, here runs the pretty nice historic tram.