One of the cool ways to get to Odaiba is not by a subway, but on a ship (called water bus, even though it does not look like a bus at all of course).
Going this route you can see nice views of Tokyo Bay, surrounding Tokyo areas and even pass under the Rainbow bridge.
Water buses could be pretty packed inside too.
This is a Sea Terminal I think.
It could get quite busy near Hinode
Approaching Rainbow Bridge
Passing under the Rainbow Bridge
Odaiba from a water bus looks pretty nice (make sure to come in the afternoon).
Incoming water bus. Nice Rainbow Bridge backdrop
Another shot of the Rainbow Bridge from the Odaiba shore
One of the Odaiba streets while there is still sun out.