The individual parts should be able to be sold with the sum of what you get for them greater than if you sold the computer as a whole. You could maybe keep the case? (maybe with a fan on that bottom fan spot, filtered), the power supply, the blu-ray rom, whichever of the DVDRW's is the better one. If you aren't going to heavy overclock, even keep the Corsair H60. The rest could be sold. Look at it this way, you save say, $140 on a new case, $140 on a new power supply, $90 on the optical drives... I guess potentially $400 saved. You may get over $200 (or even more) for the GPU, motherboard, CPU, and RAM, so you effectively 'sell it for $600'. Just to note though never, EVER write Intel Core2Duo E8400 @ 3GHz x 2 when explaining a dual core, or use x4 etc for any description of a multi-core system If you must explain its dual core, write dual core. You have only one E8400, not two of them! For the AMD chips, its different because the X4, X6 etc is a model designation, and its also a capital X.
Dave what are your future computing goals? It seems you show an interest in writing software so a test machine running VM's might be a way to use it now. How much memory will it run? and is the board quad capable?
I already run a mini business fixing Tech etc., also run a little development team as we're working on something big and upcoming in the near future and right now we're getting together often and brushing up in development skills, learning together and we each talk/learn about each other’s integrated developer environments. I must admit I have great skill when it comes to running things, but I'm going back into education soon learning electronics and computing science to add towards my future goal of running a business with my friend and competing in the ever growing world of IT. To be honest together we all have enough machines to test/run software and that's why I've abandoned the computer, and yes the board in the computer is Core2Duo and Core2Quad compatible.
The only things worth any decent cash on that build are: 1) Video Card, mid range to performance and they are relatively cheap now so used won't be worth that much. 2) The Hard Drive, the price is still a bit high on those 3) The Corsair Hydro H60, great cooler. The rest of stuff won't get you much $ it's outdated.