As others have suggested, the Prius is well suited to your driving. As I was reading your post, I was thinking that, depending on weather, you might expect MPG in the 30s to low 40s. Thanks to Ken for validating that.

Short trips will reduce your mileage of course, but you can minimize their impact by combining stops in one trip if feasible. Cold starts kill your mileage as much as anything. Keep the engine warm and mileage will improve.

Along those lines, assuming you get the Prius, consider adding an engine block heater, especially if you're in a colder climate.

EDIT: You posted your last post while I was composing this. The Highlander hybrid's propulsion system is similar to the Prius', so though the overall fuel economy is lower in the HiHy, I would guess the manner in which FE responds to various driving conditions and behaviors might be similar. But I'll defer to the HiHy owners; I have no experience with it.

Jim

Lifetime fuel mileage:

After learning how to hypermile: