This may come out a bit over but I think this is the best combination currently available:
cpuM/BgpupsuHDDCaseramYou can cut the case if you already have one. Otherwise you need to cut the GPU to a cheaper one. Everything else is too valuable as far as long term investment is concerned. It is more important to have something that you can easily upgrade down the road for a few bucks than saving $100 now just to spend $800 in the future. Also all parts here are of the highest quality as a stable system is more important than something that is just cheep and fast. This is also why they all have great warranties. Some parts like the psu and the hdd are the exact ones that I own and I can attest to their durability.