Your smartphone can do lots of things, but how much would you have to pay to get that same kind of functionality out of traditional, single-purpose gadgets? The Next Web did the maths on it, and the answer is "a lot".
If you were to buy gadgets to replace all of your phone's built-in features (camera, iPod, calculator, GPS, ereader, video phone, etc) the totally would probably come out to around $US1228, and the stack of gadgets would weigh roughly 3.6kg.
This isn't exactly a perfect analogue, but the cost is so high that you get the point anyway. As The Next Web puts it:
You should know this is a completely un-scientific process, but it's meant to be a rough approximation of how an average consumer would shop if looking for each of these gadgets. Of course, some functionalities will be duplicated across multiple devices, but that's kind of the point here.
It's also worth noting that you might not need all that functionality, so maybe you could get away with not shelling out for a video phone. Still, today's phones back a lot of punch in a convenient little package. You can take a look at the list of specific gadget replacements over at The Next Web. [The Next Web]