Are you looking for a big case or a smaller case.This makes a difference to the size of your motherboard.I used to be a big case guy but these days I have downsized to a Silverstone FT03 for my gaming build, a Bitfenix Prodigy 1 and finished, for my HTPC/spare and a Cooler Master Elite 120.
The Ft03 takes a M-ATX motherboard, which I think is the smallest you should be looking at, the other two are even smaller as they are take M-ITX motherboards. So have a look for a case then come back here with details, but just because a case looks good does not mean it is, you have to consider cooling, airflow, cable management. So pick a few and we can help you get a decent one.
Graphics card: I would suggest a GTX 670. PSU: A decent modular of 650-700W will be plenty.
I would have a smallish SSD (128GB)for your operating system and programs with perhaps a couple of 1TB sata HDD's for your games on one and music documents videos ETC on the other.
A decent cooler for your Intel 3570 i5, a Corsair H60.
Do you need a monitor keyboard and mouse with this build?