ARexx rules, and we all know it. Without ARexx there would have been no VideoToaster, ImageFX, nor many of the other apps we all know and love.
There are a few differences between proper Rexx and ARexx, but from what I'm told Rexx is fairly portable. Maybe we can see a next generation of Rexx through Regina on the open-source OS's.
Will be glad when the PPC implimentation of ARexx is finished for MorphOS :-P