UltraEdit

There is no perfect editor, and never will be. But there is an editor which is very close to be perfect for the special needs of programmers: Ultra Edit

It offers a number of features that makes it the first choice for APL programmers if there is a need to edit APL scripts outside the APL development environment:

Can deal with ASCII as well with Unicode files
User-definable font
Syntax highlighting (yes, for Dyalog APL!)
Supports fully the [:GlobalInputMethodEditor:Microsofts Global Input Method Editor]

Ultra Edit is not especially cheap, but it can be tried before buying, look at [http://www.ultraedit.com/index.php?name=UE_MoreFeatures]