As for market value for each component this isn't the place to ask that. I look on ebay's sold listings to get an idea of what others have paid for your components. There are other resources on Audiogon you can leverage to find that out. Use their bluebook or list an auction for your items.
As for whether or not you should keep your system that is for you to decide. To me if it sounds good to you then keep it. If you are bored with your system and want to try something new just unload it. Don't expect big bucks. I was trying to help my father in law sell his NAD gear and the offers coming in we pennies on the dollar.
As for whether or not you should keep your system that is for you to decide. To me if it sounds good to you then keep it. If you are bored with your system and want to try something new just unload it. Don't expect big bucks. I was trying to help my father in law sell his NAD gear and the offers coming in we pennies on the dollar.