I recently bought a 'New in the Box' HD-A35 on Ebay for $305. The value of your player is significantly greater unopened.
While Johndn's statement about electronics depreciating over time is not incorrect, that statement completely dismisses the persepctive of a potential buyer. Generally speaking, people want new things. They also want the security a NIB item provides. People on the internet do not know you and there are trust issues a buyer may also have to contend with; Will the seller actually ship the item, Will it arrive as described, Will I get refund if the player arrives DOA? Selling a new, unopened item addresses most of those issues in the mind of a buyer. Personally speaking, I will always pay more for a New In The Box item than anything described as "gently used" or "tested".
Just my two cents.