Sirkeci or in other words Eminonu is the transportation center of the touristy area. It is short walking distance to Sultanahmet square and all ferries, bus connections and tram connections are beig made here. As it is in close distance to most ot the important sights and walking distance to Train station, ferry terminal and main tram stop, it attracts many tourists.
Around the Sirkeci area, you can find many hotels to stay. There are also many budget hotels. The area is decent and silent at nights, however quiet busy and lively at day time. If you plan to have long nights Sirkeci shall not be a good alternative, but still it is the main connection area to other parts of the city.