I will add a gpu at a later point. Probably SAPPHIRE 100315L Radeon HD 6850 1GB 256-bit GDDR5 PCI Express 2.1 x16 HDCP Ready CrossFireX Support Video Card with Eyefinity or an NVIDIA card because it supports CUDA
I am assuming you intend to overclock according to what you have selected, so i would leave out the Asrock board because of that.
The Asus board is a much better overclocker. It also comes with better warranty.
The gigabyte is a good board, I actually use one in my i5 2500k system, but the problem is that it doesn't support PCIe Gen3 so it's lacking some future proofing.
That being said, since you don't really intend to do gaming you will probably do fine with a PCIe Gen2 board. And generally the PCIe Gen2 16x will be quite sufficient for handling the level of graphics you intend to install.
So either of the options is fine, just don't get the asrock.
As for case:
depends what you are looking for in it and what your budget is, but you can get good basics at about $50-60
like Rosewill Challenger U3, Antec One, Cooler Master HAF912
Then at about $100 you get to the next level of goodness and like Lian Li aluminum cases, Cooler Master HAF 922
The when looking at $130-150 you get to ones like Cooler Master HAF 932, NZXT Phantom, Corsair Carbide 500R, Rosewill Thor
All good cases , but just depends on budget and what you are looking for: Looks, Connectivity, Cooling, Sound profile, Expandability etc.
SSD: Unless you are going for the highest possible reliability, you should probably look at SataIII and sandforce based drives or Crucial M4 or Samsung 830
You should be able to get a either a faster 64GB model or up to 120GB model which would still be faster than the 80GB Intel drive.