Yes. I mean, dont get me wrong, I wouldn't call them a sound investment but they hold their value aswell as any computer hardware ever seems to (depreciates less would be a better way of putting it ).
There's literature about on this topic.
http://blogs.smartmoney.com/paydirt/...pple-products/
http://www.ign.com/boards/threads/wh...ade.250064175/
http://www.everythingicafe.com/iphon...ds/2012/02/09/