More specifically narrow down the choices by checking which versions support the hardware (WLC and APs) you'll be using. Then look at the features you want to use and that may narrow your options further. Then go for the latest build of the major release which you select.
FYI: 8.0.152.0 (which is available) is MD not ED but I wouldn't recommend it as it's close to end of support so if your hardware is supported in a later release you should probably be looking at minimum 8.3.
