Essentially—and some might argue for either better or worse—iTunes is a file manager.
In fact, I usually will tell people to just forget about the files. Let iTunes deal with them. Most people will never need to examine the files inside the iTunes Media folder.
OTOH, I do all kinds of twisted things to tags and metadata and I often need to know how that may have affected the location of a file. Or sometimes I'll need to know if a file is where I think it is or is still named what I thought it was.
This information isn't handily available (although some Smarties will copy the file path to the Comments tag so it is viewable in the Comments column in the browser window). You can reveal a track's file using iTunes' "Show in Finder" command or see its file path in the Info window's File tab, but this uses up valuable finger time. And the Info window is modal; you can't run scripts when it's visible.
So I made this simple stay-open applet that will monitor iTunes and display the file path of the single selected track.
The window is resizeable horizontally and the text is scrollable.
The Display File Path window will float alongside iTunes and whenever a single track is selected—and its file is accessible—the file's path will be displayed. The displayed file path can be copied as text to the clipboard and the file can be selected in the Finder. There's also an option to show the file paths of each playing track instead of the single selected track.
Obviously, it's only useful for occasional special jobs but I've been finding it handy when the need has arisen. It's free to download and use with a donation nag and is available here.