Consumer vs. business computers, is there a difference?

Working with many different small businesses we often get asked this question. Frequently purchasing a new computer is left to the last minute and at first glance is seems easier to run out to the nearest retail store and pick up a shiny new system. In addition these same retail stores are often advertising systems at great discount prices, but is it really cheaper in the end? What’s really the different between the consumer models found in retail stores and the business models available through resellers or directly from the manufacturer?

When comparing different computer models the conversation quickly focusses on the technical specs.