The cpu 5355s are cheap, $100. So would an SSD 120GB. Both are nice returns in performance. RAM is much cheaper AND better than ever was, so that too. Spread them over one a month if you want. The only hard one is $250 ATI 5770 but having done that recently when I upgraded to Lion in March it is a solid card even today even on a 2012 Mac Pro for most except hard core gamer or if you need $600 CUDA workhorse, some do.
I chose to buy 1,1 also with 2.0GHz 4-core and it is okay - SSD helps a lot, as does memory, but I have trouble at times with cpu upgrade. It would though make sense for you.
The Sonnet Tempo Pro is nice or the non-Pro edition for just one non-RAID (put the money into 500GB $320 SSD) for scratch - not bootable in our system.
16GB RAM (8 x 2) $120 can't be beat. Paid $150 for one 512MB FBDIMM originally ($300 set). That is what a good solid minimum for CS6 or any graphics, though if you do a lot of work more would help.
Finish it off with 3 x 2-4TB WD Blacks and 1 x 3TB WD Green for backup or idle projects.
Remember, you have four drive bays, one for system, three more, and two Optical Disk Drive SATA ports you can run cable off on the motherboard to go out the back (easy) (always on, can't turn on/off drives on those at switch) or put a drive up in lower optical bay (when you do cpu upgrade).
Sonnet Tempo SSD PCIe can hold two SSDs.
Lot of storage you can put in there.
I want to wait a year if possible hold back and let the new hardware, drivers, and of course Maverick has a lot of changes so let those get ironed out and 4-6 months for software to play catch up and tested. My fear was price for entry model and cost of one or two Thunderbolt expansion cases on top of that.
