I have encountered this annoyance a thousand times when installing software: setting the path on where to install the software.
Too many times have I been into the trouble of cleaning up a messy installation. I remember one time when I was installing that hex editor in which I specified the installation directory different to the default. I have set it to my custom programs-directory, D:\Programs\. That is when my head started to ache: the directory's now full of garbage. Filth! .exes and .dlls are what I see most in it, in addition to some folders I have almost mistaken for crapwares.
Now I am more careful, and paranoid. I now put my installs in their own container directories, in subdirectories of D:\Programs\. Still, carefulness has its price. I now encounter more "double directory" installs than the number of mess-prevented installs.
Here is my point: How should I prompt the user for installation directories, especially if they are required to set it? How can I make the request more intuitive and less error prone?
Note that I also mean this for save directories, configurations, etc.

