I've been road tripping for about a week now and as such have seen a lot of public toilets. I've seen everything from the grubbiest rest stop outhouse to the marble-walled stalls in the parliament building.
My favourite were the composting toilets we saw at a few of the more secluded rest stops on Vancouver Island. They flush like a real toilet. Well, sort of like a real toilet. More like the ones you see on buses and airplanes where they have a little door that opens when you flush. But they are definitely not stinky and gross like outhouses. I don't entirely understand how these work, but the idea is fantastic. More research will be done into this style.
My next favourite can be found at most Tim Horton's restaurants. These are the ones with the two buttons. One for number one and a slightly bigger button, suitably for number two. This is becoming a popular option for water conservation. And I think it's brilliant. You need to be able to have enough water to get the coilers down, but that is not necessary for every trip to the little girls' (or boys') room. I can see how this would be the more popular option, but maybe they should combine these two to make a super eco toilet!
Then there's the auto flushing toilets! I hate these with a passion! Not only does it require more energy to run the damn thing, but often, if you need a little extra time on the john, it will flush while you're still on it! Or before you're completely done wiping, so you have to make it flush again. This is such a waste of water. And there's often a bit of back splash if it goes off while you're still sitting down. Ew!
If I ever get the chance to build my own home, I think I'll go for the composting toilet. As long as I can convince my husband. :P