I agree with bloodline. If you want a modern system that will run anything you want, you want aros, of course it depends a bit on what you want to do with it... If your looking to run classic games and apps, I think amiga forever or AROS are the best choice.
Os4 and morphos will not run very demanding 68k games or demos without major frame skipping, sound problems and slow downs.
So if you want a system that will run any legacy amiga software, and also some modern apps, I think aros is the best choice.
