Our Sienna Limited Fwd is still in break-in, so mileage can't be fully rated (we've averaged about 14 MPG overall, but have less than 200 miles on the vehicle, almost none on open highway). The Bluetooth integration and backup camera are must-have features, IMHO (for safety alone). The nits are minor.
Backup camera, Bluetooth integration, support for WMA and MP3 CDs, AUX inputs for both audio and video.
Tie memory settings to key fob, and allow the seat position to be recalled before the vehicle is started.