Graphical user interfaces (GUI) Databases Web programming Working with XML Using Regular Expressions Parsing Mathematical Expressions Writing a Basic Type Checker
Good tutorials where to start
Also see Haskell/Pattern matching (absolutely not the same as regular expressions in Haskell, but instead of trivial regexps, it may be more elegant).
Graphical user interfaces (GUI) >> Databases >> Web programming >> Working with XML >> Using Regular Expressions >> Parsing Mathematical Expressions >> Writing a Basic Type Checker
Haskell Basics >> Elementary Haskell >> Intermediate Haskell >> MonadsAdvanced Haskell >> Fun with Types >> Wider Theory >> Haskell Performance
Libraries Reference >> General Practices >> Specialised Tasks