Smart Indenter from BMS Ltd.
www.bmsltd.co.uk 
Source Code Control
Use Sub Version with Tortoise Svn. Gives you a far greater user experience than Visual Source Safe.
Code Libraries
Misc
Lots of different tools for Microsoft Office and VB at:
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: www.mztools.com
For more information about alternatives on Visual Basic, please refer to Accede Solutions: accede.com.au
UCalc Fast Math Parser www.ucalc.com
Testing tools: Vb Lite Unit, Vba Unit, Vb Unit, Com Unit
See original on c2.com