Does anyone know what is the best way is to create a highly attractive
presentation set of screens for a (large) intranet Internet based
business software application?

There are some screens in the application that are used by 100s of
users all days every day in a typical configuration/installation.

An attractive presentation, providing access to 100s of functions, and
it
being obvious to a first time viewer that these are available, is
important.

The 'first time' viewer is important, ie a sales prospect for using
the large business application.

Is C# better, or using Java widgets and control?

Any help out there appreciated.