Building a litecoin rig on the side too. I guess I'll leave btc.
Who says you can't do both? Trade ~29 LTC for one bitcoin. The difference is it takes 20 days to make 29ltc with a $2500 GPU investment, instead of having absolutely no chance in hell at return unless the bitcoin exchange rate keeps climbing buying sha-256 hardware. Not to mention old Sha-256 hardware will be useless for anything some day soon.
Less than two months and your investment would likely be paid off. Then you sell the GPU rig and really make profit.