Shower head with nice conical flow
I have found that a Navy Shower Head does a great job of wide spray (for hitting your entire body at once), good pressure (for washing hair), and it's rated low-flow so you should be able to get 2 hot showers back-to-back (provided you don't take 3-hour showers). 

There are a few items called "Navy Shower Head"--this is the one I'm referring to: https://www.build.com/delta-52652-pk-shower-head/s244417?uid=1907341 You should be able to find it at most big-box home improvement stores and online.