Hello and welcome to the forums mate
If u want to go for shuttle then IMO go and buy one of their barbones instead because the power supply of shuttle is different with others.
But if u want to build yourself then go for either silverstone/TT case instead.
Your rig looks very nice however instead of a 16MB HDD u can go for a 32MB one i dont think the price difference is much.
Well from my experience doing up SFF/mATX gaming rigs best is u have a modular 80+ PSU for neater cable management and hence promoting better airflow. This is what i came up with:
$ 27.00 ship
$ 20.00 MIR
$691.92 Total Expenses