The only way you can tell an Accord Hybrid apart is by the dead silence at a stop and the badge on the back. Otherwise, it looks just like a regular Accord, inside and out (though you do sacrifice some trunk room).
You don't sacrifice much. IIRC, it has run-flat tires and uses the space formerly occupied by the spare tire. I think the trunk's dimensions end up being the same except the trunk floor is about 2" higher.