well obviously HTML is used for making websites. (and is also used to make the pages of .chm help files)
ASP, coldfusion, PHP and PERL are used for making server side active pages.
PHP and PERL can also be used for making scripts, (Like batch files)
batch files are used to run multiple task and selections.
macromedia action script files can be used in flash files (I think) for either server side, or client side
Visual basic is used mostly for business applications.
C is mainly used for small applications such as low level opperations, (network / maths etc...)
whilst C++ is used mostly for window aplications, and games (note I say window and not windows since C++ is used for programming in Linux as well), there is a saying that there is nothing that can be done in C that can't be done in C++, however that doen't necessarily mean that c++ is the best tool for the job all the time.
vbs (visual basic script) is used from scripting (like logon scripts) but can also have windows elements and call other procedures such as microsoft agents in help files...