Which skin to select?

I would like a skin that shows the following information:

- list of all files in a given directory. (I do not want the library view since this mixes all files)

- picture of the movie/box/...

- short description of the movie.

So a bit similar to e.g. Front Row or Xperience's Tri-Fold but both only work in library view.

what do you mean by mixes files? Library view is sort of the whole point of xbmc. I don't think it can display movie info/descriptions when it is not in library mode.

In Library view I get a list of all files/movies (unless selecting by genre/year/etcetera). I want the other view in which I see and can select (sub)folders.

You should try the integrated File Manager.
You'll find that in most skins.

Use local artwork and file mode which is in all skins my advice is try them all and find the one you prefer your not going to get any movie details or flagging in file mode but if you want to browse by directory then your have to do without it

Why exactly do you want to browse by directory because there are other ways to separate whats in your library, Smart Playlists for example can be used to show whats in a chosen source plus a hundred other rules