Perl is not in itself a windowing client but it can
drive libraries which display windows, as with Tk.
images in Netscape which automatically highlight on
mouseover, Perl can
modify that file on the fly to specify which images
should be drawn. You would modify a template
If a gorgeous interface is the most important thing
the answer to the front end. Java or Perl can be used
on the back end. Personally I find Swing too heavy
and you can probably get everything you need for a web
app through DHTML.