Actually this is retarded and wrong
Every iPhone I have owned, I have turned around and sold within 2 days on CL for the same price as a new phone.
Example... I sold my iPhone 3G for $300 the same day that I picked up my new iPhone 3GS for $299.
IMO this is one of the best products ever as it holds 100% of its value in 2 years. Every other phone is shit compared to this