RMXP is obviously the best choice for creating an RPG. Game Maker kicks very much ass at making ANY kind of other game, and the folks at the GM forum REALLY know how to help you (very fast, I might add), so it's hardly necessary to learn the GML. All you gotta do is ask how to do something on the forums, and you got like 5 replies in less than ten minutes telling you exactly what code to put in. @__@
I like Multimedia Fusion 2, though. =D You gotta be pretty clever to get some of the effects that are fairly simple on other apps, but it's the most reliable for making a platformer.