Spyder is a great python development environment available through Python XY on Windows. Getting it to run on Mac OS X is a little more complicated however. You can't just download a binary image (.dmg), you need to compile the code from source.
The easiest way i found is to use MacPorts which comes with a package installer (think setup file).
Prior to installing MacPorts you need to install Apple Xcode and Xcode command line tools (Xcode Preferences - Downloads)
Run Port selfupdate
install py-spyder - This should include most required dependencies including python 2.7, numpy etc.. and because of this it takes a while
then open spyder from the terminal
As i said before most required python libraries should be installed using this method but not everything included with python xy. If you find you need a module that is not installed chances are you'll be able to find it on macports. If unsure ask and google.