All-in-one devices? Or separate technology?

My professor posed an interesting question in class the other day.

Do you want technology that is all-in-one or do you like separate devices?

For example, why do we have iPods, cell phones, portable DVD players for flights, Blackberrys and digital cameras? Granted, the device that can do all of these things may not be out there. Or is it? Or do we like our separate devices? Something to ponder.