my town layout now is the very first one that came up when I started up the game for the first time. I didn't know people even did layout resets until I joined this forum, and by then I was too attached to my town to reset. plus, I really like my layout anyway! I'm not sure everyone would? but I worked with what I had.
if I were to start up a new town now, which I've been thinking of doing eventually if the game goes on sale, I would look for a layout that either has a river running perfectly through the middle, or one where the river creates a small bubble/island, where I'd put my mayor's house. I'm not sure I have a preference for the waterfall direction, but a secret beach would be cute. I also want minimal ponds! 2 at most. my current layout only has one. I'd like townhall and the plaza to be close to the train tracks, but I'm not too picky about re-tail.
I like the top and bottom halves of my village to be roughly the same size. My town hall is up to the far left, and my Plaza is down below to the left also. Retail is in a convenient spot, right by a bridge. The river isn't all huge, just a big pond on one end. This is how I like a town to be, I chose this map as soon as I saw it. The town hall and plaza don't have to be in these spots, so long as they're far apart. My only gripe is that there are like five ponds, which I don't like, and rocks in bad spots. But overall I like the layout.