Web browser will be the most popular GUI front-end in the future. It is recommended that you migrate all of your "legacy" Windows 95/NT applications to Web-based application.
You should use Web-Application Servers like Enhydra (Java based) or Zope (Python based) or OpenACS .
Best web-scripting (and compiling) language is PHP+Zend compiler PHP is extremely powerful as it combines the power of Perl, Java, C++, Javascript into one single language and it runs on all OSes - unixes and Windows NT/95.
The best tools in the order of preference 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 an IDE (integrated development environment) for Tcl/Tk called SpecTcl.