asus z75 pro3 queston

I would advise something with good ventilation. Whatever case you decide on make sure it supports ATX form factor boards, some only support mATX or smaller (ITX). I am using a cheap DeepCool Tesseract and it does the job well. It isn't the most sturdy of chassis so not ideal if you move your system around a lot but for a system that will spend its life on or under a desk it does a great job. Decent cable management facilities and great ventilation (provided you add a couple of extra 120mm fans). It comes in 2 variations (aside from trim color) one with a window and the other without depending on your preference. For a budget case it is a great choice but if you are looking to spend more then I would look at Lian Li, Thermaltake, Thermalright,  Cooler Master and Corsair. All those brands have some very solid mid/high end cases on offer.