Visual Basic Tools

Smart Indenter from BMS Ltd. http://www.bmsltd.co.uk/Indenter/Default.htm

Source Code Control

Use SubVersion with TortoiseSvn. Gives you a far greater user experience than VisualSourceSafe.

Code Libraries

Misc

Lots of different tools for Microsoft Office and VB at: http://www.fmsinc.com

Auto-error handling code, generated 'select case's, code templates, 'Calling functions', better search, and lots of other useful items are provided through MZtools: http://www.mztools.com

For more information about alternatives on Visual Basic, please refer to Accede Solutions: http://accede.com.au/

UCalc Fast Math Parser http://www.ucalc.com/mathparser

Testing tools: VbLiteUnit, VbaUnit, VbUnit, ComUnit