My experience from being a customer is that you definitely want to be able to sell the Mac as a TOOL and not as a TOY.
The other day a new Best Buy opened in my city so I dropped in to have a look. I walked up into the Mac section and someone was eyeing the 20" iMac. Unfortunately, some wag had previously pulled the shift-cmd-optn-8 trick so the screen colors were completely wrong. I was like, "Wow, that's not right" and fixed it so the other customer wouldn't be completely unimpressed. He figured I must be a Mac guy, and started asking me questions about buying a Mac, switching from a PC, what I would recommend, etc.
I was answering his questions based on practical experience, and trying to show him the ways that a Mac would make his life easier. For example, I went through iPhoto and iDVD, demonstrating how easy it would be to take photos from his digital camera, bring them into the computer, make a slide show, and burn it onto a DVD (complete with motion menus).
By this time a sales guy had come and was starting to try to take over the "sales pitch". I had things to do so I left them. I could hear them talking, though, and the sales guy started trying to impress him with technical features and "toys" -- like how the Dock was reflective, or how Spaces would animate in and out. He didn't seem too interested.
Demonstrate how the Mac will make your life easier, or increase your social standing (e.g. the first time you pop in a DVD you made and those motion menus start). Don't try to sell them on flashy glitz.