The D7100 has two U settings, which I use mainly when traveling.
U1 is the "hand off" point and shoot mode, for when someone offers to take a picture, etc. Rather than explain various things, I just set this one for P, Iso 400, shutter button focus, and so on.
U2 is a rough duplication of my usual starting point, and when I am in unusual circumstances, or experimenting, and need to shoot at some odd ISO or mode, I start there. Since U settings revert to their starting point when switched out, and since they don't affect the normal settings, this avoids the occasional issues when I get up in the morning, forget that last night I forgot to switch back out of 6400 ISO or drastic negative compensation or whatever.
If I had a third U, I'd be inclined to copy Akira's panorama setting.