If you want to do the touristy things, hotels along the Bund and around People's Square are the most convenient. BTW, people that fill the Square, E Nanjing pedestrian road and along the Bund are mostly domestic tourists, not real locals. However, if you want to stay in quiet and nice residential areas, then something like IC Ruijin, 12 Hengshan, or even Radisson Blu Xing Guo makes more sense.