Nice rig, as to what it's worth? That depends on whether you sell it to a mate or put an ad in the local paper or stick it on EBay or even split it down to its parts and sell them separately.
If you sell it to a mate then perhaps deduct 20% off what you paid, you could maybe get a bit more selling it locally. If you stick it on the bay then you will probably end up with less when you take the fees fom Ebay and PayPal into consideration. As I am assuming you did not build this rig yourself then splitting and selling the components is not really an option as whoever you bought it from would have put their bit on hence the price you paid for it.
I could give you a rough breakdown of what you could get if you split. But I would try, if I were you to sell it complete.