Ortakoy is great but sort of out of the way (see CC threads for discussion). Takism is great for food and drink at night but you indicated that isn't the scene you want. The DoubleTree is probably your best option. It is closer to the tourist sites and right off a metro line. That being said, taxis are relatively cheap so any of the locations you mentioned are fine (note traffic in the Old City is horrible and even Felix Baumgartner is scared to drive there)