You could try Spyder which is multi-platform, easy to use, provides syntax coloring, interactive debugging etc. You will still rely on libraries such as matplotlib or NumPy, and the IDE itself may not be good enough if you are dealing with very large sets of numbers.
There are also other similar projects such as Python(x,y) or WinPython (Windows only) that try to promote/facilitate the use of Python for scientific and engineering software development.
