Timo
You do realize that we are talking about signatures identifier, right ? You asked suggestions on more features to your app. So, a signature identifier is not only to identify a packer but, libraries, images, specific data in the resources section etc. Take a look at flirt technology and you will see what it is all about. It also helps to avoid your app to crash on some problematic files (not necessarily packed) but containing different ways to display the data inside the sections of a PE, like in some Watcom files for example, or can help identify files whose section were not properly aligned etc etc.
Agree with Jochen and Vortex. The app is excellent, although some more features may be necessary. What about loading old file types, such NE executables or Name unmangler on the apis functions, recognition of delphi structures in the resources section etc ?