What are the best End-User desktops for Desktop PC's?

Some apps have really rough edges, for example:

• Caja: by open an SVG-file and get a Dialog with 4 Buttons(Run in Terminal, Display, Cancel & Run) at least two of them make no sense. You can also right click on them to choose the application, however you default application for that filetype is not on this list.
• Panel: Empty panel applets are about 1px wide so you really cant resize or move them to organize your panel.