in my option,currently the best ide for py is apanta,becasue it provide a standalone package contains all want you wathnt,it's base on elipse,and do some extension & integaion,it's good for ror,but i use it for py.
before apanta i use komodo edit,it's free &oen source, it's suit for me to write some daily script ,but if you want to manage a projcet with one file more than 700 lines,it's feature is not enough suit this situation,so i began to chance another ide,also the performance under xul,is a another issue