Web browser will be the most popular GUI front-end in the future. A major portion of code should be written in Web server scripting (and compiling) language PHP/Zend PHP and with little bit of JavaScript on web-client side. It is recommended that you migrate your legacy Windows 95/NT applications to PHP/Zend.
The best tools are
Language choices in the order of preference are -
There are other tools available - PostgreSQL has Tcl/Tk interface library in the distribution called 'pgTcl'. There is a IDE (integrated development environment) for Tcl/Tk called SpecTcl.