I find the File Operations component of Foobar2000 very useful to delete MP3 files in my playlist. The default delete only removes the track from the playlist, but with File Operations I can delete it from the playlist and the disk (which is what I want).
To do this, right-click on the track and from the context menu choose File Operations → Delete File.
The only nitpick I have with File Operations component is that it does not seem to be available on the Foobar2000 Components page. If you need it you need to choose it during installation from the Optional Features section in the Choose Components dialog.