Enthought's free distribution of Python--Python Enthought Edition--which includes several pre-compiled libraries hand-picked for scientific data visualization and manipulation, all in an easy windows installer.

In addition to all of the features provided with the standard Python 2.4.3 distribution, Python 2.4.3 for Windows (Enthought Edition) also includes the following packages:
celementtree 1.0.5-20051216: C extension XML parsing
ctypes 0.9.9.6: A package to create and manipulate C data types in Python
Docutils 0.3.9: text processing system
elementtree 1.2.6-20050316: XML parsing
Enthought Tool Suite 1.0.9: A tool suite for building extensible python applications. This includes chaco, traits, kiva, envisage, etc.
epydoc 2.0: Automatic API Documentation Generation for Python
fpconst 0.7.2: Utilities for handling IEEE 754 floating point special values
GadflyZip: An SQL Relational Database in Python
IPython 0.7.2: A Python Shell done right.
Matplotlib 0.87.3.2478: Python 2D plotting library
MayaVi 1.5: 3D Data Visualization Tool
numarray 1.5.1: STScI rework of Numeric
Numeric 24.2: Numerical Python
NumPy 0.9.9.2706: Basic N-Dimensional Array manipulations
PIL 1.1.5: Python Imaging Library
pydot 0.9.10: Python interface to Graphviz's Dot language
pyparsing 1.4.1: Python based grammar parser
pyreadline 1.3: ctypes-based readline for Windows
pyserial 2.2: A python extension for accessing the serial port
PySQLite 2.2.2: A Python Extension for the SQLite embedded relational database
pysvn 1.4.1: Python interface to subversion version control system
pytables 1.2.3: Package for handling hierarchical datasets
pywin32 208: Python for Windows Extensions
PyXML 0.8.4: XML Tools
ScientificPython 2.4.11: A collection of Python modules for scientific computing
SciPy 0.5.0.2033: Scientific Library for Python
SOAPpy 0.11.6: SOAP/XML Schema library
TestOOB 1.1: Advanced unit testing framework
VTK 5.0: 3D Visualization Toolkit
wxPython 2.6.1.0: wxWindows for Python
ZODB3 3.6: ZODB and ZEO Object DataBase