If you don't choose Tk, other options include wxPerl, Win32::GUI, and writing a web application so that your browser becomes a GUI.

Any of these can be justified. I often go the web route since the database that I need to work with is centralized, and I don't want to deal with making sure that each system is set up correctly. But YMMV.

UPDATE: Switched the words "browser" and "GUI" per BUU noticing that I had them reversed from what I meant.