Both Roppongi and Akasaka are great central places to be based, with good transport connections and a wealth of top-class eating, drinking and shopping options on your doorstep. However, check that your hotel isn't too close to the main bar and clubbing area: in Roppongi it's from the intersection of Gaien-higashi-dōri and Roppongi-dōri up until roughly where the Axis building is. Akasaka isn't too bad for this kind of noise.