The new version of the free open source plug-in that turns Visual Studio into a Python IDE has support for virtual environments and debugging improvements.

Python Tools for Visual Studio (PTVS) was first made available as a free plug-in two years ago. Since then it has added support for Windows Azure web sites. 

It is a free open source plugin for Visual Studio. It is an officially supported Microsoft product and it works with CPython and IronPython as well as Python 2 and 3. What is more you don't even need to buy a full version of Visual Studio. If you down load the free Integrated Visual Studio Shell and install PTVS then effectively you have a Python Express Edition of Visual Studio.

Now the alpha of Version 2.0, has been released with improved Intellisense.  This video demos the enhanced filtering and analysis capabilities and the new Navigate To facility:

PTVS 2.0 adds a Debug as Script feature which allows you to debug any Python script file, without a project, using Visual Studio and provides the ability to set breakpoints, break all, inspect state with the call stack, locals and watch windows.

(Click on screenshot to enlarge)

An overview of Debug as script is provided in this video

and this one covers the new facilities for remote debugging on Linux and OS X that don't require extra processes:

There is also support for Virtual Env in PTVS 2.0. At the moment this is at an early stage and the Python tools team at Microsoft is looking for feedback from devs who want to use it.

If you have a copy of Visual Studio then PTVS gives you access to arguably the best IDE available for Python development. Comparing IDLE say to VS with PTVS makes IDLE look like a joke.