The GX series is something I would not recommend, as they don't have a very high temperature rating and can actually shut down due to OTP at high loads at high temperatures (above 35C). Thankfully the case you are looking at, the M59 mounts the PSU at the bottom, so hopefully it shouldn't have to deal with heat from the rest of the system.
I would suggest looking at the Cooler Master HAF 912, as it is probably the ultimate case for $60 imo.http://www.newegg.com/Product/Product.aspx?Item=N82E16811119233
Apparently the Rosewill Challenger is a good buy as well, altho I haven't checked it out yet myself so don't know much about it.
Other cases at that price point which I would consider would be the Lancool PC-K56 and Xigmatek Utgard.