I see a lot of people asking about script editors for vbScript and Powershell.

If you want free then I would suggest the following:

 Notepad Plus is a good replacement for Notepad.

http://notepad-plus.sourceforge.net/uk/site.htm

Here are the features of Notepad++ :

Syntax Highlighting and Syntax Folding

Supported languages :
    C C++ Java C# XML HTML
    PHP CSS makefile ASCII art (.nfo) doxygen ini file
    batch file Javascript ASP VB/VBS SQL Objective-C
    RC resource file Pascal Perl Python Lua TeX
    TCL Assembler Ruby Lisp Scheme Properties
    Diff Smalltalk Postscript VHDL Ada Caml
    AutoIt KiXtart Matlab Verilog Haskell InnoSetup
    CMake YAML

WYSIWYG 
User Defined Syntax Highlighting 
Auto-completion 
Multi-Document 
Multi-View 
Regular Expression Search/Replace supported 
Full Drag ‘N' Drop supported 
Dynamic position of Views 
File Status Auto-detection 
Zoom in and zoom out 
Multi-Language environment supported 
Bookmark 
Brace and Indent guideline Highlighting 
Macro recording and playback 

Or you could go with Sapiens PrimalPad:

If you are only working in Powershell then:

 the Power Gui from PowerGui.org is a good choice and it’s free:

http://powergui.org/index.jspa

 For a few dollars more;

Try EditPlus

http://www.editplus.com/register.html

One just for vbScript is vbsEdit;

 http://www.vbsedit.com/

Of course if you want the very best and are willing to pay for it then you must buy Primal Script.