Hi Bonnie and Glenn,
Actually this option already exists in Visual Studio, but it is only available for native code (C/C++). It is located on the "Debug >> New Breakpoint >> New Data Breakpoint" menu item. The problem is that it will be always disabled when working with managed projects. Very unfortunate indeed, because it would be a very usefull feature to help findind those nasty bugs that insist to come up once in a while <g>