"because Apple products tend to hold their value a lot more than normal computers."
Sorry, but Apple kit is equally "normal" and as for "value" I consider them rip-off prices (that's why Apple is perhaps highest valued company in the world - if over half of the retail price is profit, they're worse than jewellers for overpricing, esp when you think of the Chinese sweatshops where it's nearly all made).
Don't get me wrong, I have 5 Apple iMacs and some older gear, but these iMacs were all 6+ years old when I bought them on Ebay (none more than 200 quid). Only problem with that is that newer software (OSX 10.7 and later, and even newer versions of Chrome browser) cannot be used on these (only 2 of the 5 can run the Chrome browser because they have Intel processors... the others, with Apple G5 CPU cannot run Opera or Chrome, just rubbishy Safari).
I think some Apple owners on Ebay are extraordinarily "precious" about their used gear as many refuse anything but collection in person, even for kit dating back to 2007/8/9. I don't understand what they think will happen, unless they believe courier firms will break the computer in transit!
Apologies for the 'grumpy old man' appearance of my rant. Been working all night and really do not understand why even second hand in CEX, there's some idea an Apple computer should fetch 700 or 800 quid, twice the price of something running Windows. There's still heaps more software for Windows and far less "innovation" coming from Apple these days...
OK, OK, the new iMac at $2500 has higher resolution screen than anything else, but heck, why don't they build it to use a 50" wall mount screen (or a projector) that can give that number of pixels some purpose... I use 32", 40" and 42" screens with my Apple and Windows kit for films etc...