What's the standard for screen resolution for forms that are to be included in over-the-counter software to be sold in stores and used in homes and businesses.

I always thought/assumed it was 640x480. Or is it 800x600 now? I know it also depends on the application, but as a rule or on average what is considered the best screen resolution to use when developing a form in VFP that might some day be sold to the general public?

What do you think? Thanks for your input.