Delivery drones seem to be catching people's imaginations, and various companies, including UPS, have been making preliminary tests. I have recently become interested in drones (specifically quadcopters) myself, and I honestly find my at a bit of a loss understanding where drone deliveries would fit into the scheme of things.
A typical non-military drone big enough to deliver anything other than a package of contact lenses would typically be some kind of multi-rotor, like a quadcopter (four motors/props) or hexacopter (six motors/props). These are electrically powered and can usually fly for 30 mins or so, at speeds up to around 50mph or thereabouts.
Current models, such as those used as camera platforms, can use GPS positioning and can be made to fly at specific heights, etc. I can't really see how drones could be used in an urban setting, too many obstacles and obstructions.
The suburbs becomes an issue of flying time/distance, depending where the deliveries originate from - and would you not need to be present to receive the package? Are we just dropping packages in peoples back yards?
The one thing where I could see some kind of drone delivery being useful might be dropping emergency medications to someone stuck during a flood, or some kind of similar situation where the delivery vehicle can't safely get to a given destination.
Other than humanitarian aid, I don't really see the appeal, other than it "sounding cool".