This is actually an interesting question!
I am starting to experiment with AROS on Ubuntu on Parallels (OSX).
Of cause it depends on what you want to aim for. (AOS, AROS, AOS4, MorphOS...)
I find the lack of easy to set-up dev-enviroments one of the main obstactles to return to Amiga Development... (yet AROS was reasonable easy) but maybe I havn't found the right solution.
