I have not used perl/tk: the syntax turned me off. I have used Gtk-Perl. I like it a lot and have done some significant projects with it (sorry I cannot provide pointers, they're for the clients' internal use only...). I had done some Gtk programming in C before using Perl-Gtk so I knew a few things about Gtk, but the perl interface is much easier to use. Rather than list the capabilities, here is a list of the modules (from the website):

• libgtk The base module (Gtk and Gtk::Gdk namespaces).
• libgdkimlib The Imlib module (Gtk::Gdk::ImlibImage namespace).
• libgdkpixbuf The Pixbuf module (Gtk::Gdk::Pixbuf namespace).
• libgtkglarea The OpenGL widget module (Gtk::GLArea namespace).
• libgnomeui The main Gnome module (Gnome namespace).
• libgnomeprint The GnomePrint module (Gnome::Print namespace).
• libgtkhtml The HTML widget module (Gtk::HTML namespace).
• libxmhtml The alternate HTML widget module (Gtk::XmHTML namespace).
• libglade The Glade interface files (Gtk::GladeXML namespace).

There is lots of stuff and it seems to be a fairly complete Gtk implementation. Lots of tools are built with gtk, but I do not know of a statistic for apps built with Perl-Gtk. Based on the queries on the mailing list, though, there are some pretty interesting ones.

--traveler