Is it worth cheap workstation to upgrade or just spend on desktop?

Hi,

I'm currently studying architecture so I do a fair bit of rendering (Maxwell) and use the CS4 creative suite on a daily basis as well. For these reasons, I think that a workstation would suit my needs better but the prices seem to be pretty crazy compared to desktops.

I was looking at MU_Engineers build for a low-end workstation:
1. Build #1: Budget general-purpose workstation
- Processor: 2x Opteron 4180
- Motherboard: MSI MS-91F7
- RAM: 4x Kingston KVR1333D3D4R9S/4G (4x4 GB reg ECC DDR3-1333)
- Graphics card: would largely depend on what you're doing with the machine. Since this is Tom's, I'd say a Radeon 5770 would be appropriate.
- Hard drive: your favorite 128 GB SSD as the OS drive, 4x2 TB WD Green in RAID10 as the data drives
- Case: almost anything ATX or bigger will work, but let's say the Antec Nine Hundred since I am familiar with it.
- Power supply: any decent 600-700 W unit
- DVD burner: pick any SATA DVD+/-R/RW unit you want to.

Would it be possible to just buy some of the parts and upgrade the rest at a later date or will I just be shooting myself in the foot: e.g.
1 x Opteron 4180
2 x 4gb Kingston
1 x 128 GB SSD
case, power, etc. similar to above

For graphics, maxwell runs of CPU (at the moment anyway) so I wouldn't be spending that much on a graphics card...possibly upgrading later if I move more into CS4 or a GPU based renderer (e.g. fryrender).

Thanks,
Z