Rule of Thumb - Take your build cost and then subtract 10% the next morning you wake up after you build it .... then 5% for each month of age for 6 months (60% value at this point) ... then 10% for every 6 months thereafter.
If you are 3 years old .... you're down to 10% of build cost.
Jack I beg to differ. That is one very incorrect formula for a real life application like this. His computer can run games pretty decently in the condition it is in, there's no doubt. The only bottleneck I see are those ATI cards. Which is where I get to the point I was going to make... This is quite expensive for such a build. If I was someone who wanted this I'd fork up $800 max. Just helping you out mate.
1200 is a really steep price for that build. Its also kind of old... Sure it has a real nice amount of ram, but the CPU is kind of old. If I were you I'd leave 8 GB of RAM in the system, and sell the rest individually. I'd advertise the system for 800 OBO, and I still think thats giving it a bit more credit than it deserves...