Day to day I use Visual Studio for ASP.net and CSharp. It is okay-ish. I used to like Visual Studio then around version 6/7 it went rather multipurpose/multilanguage and lessened the experience. Nowadays it needs a lot of horsepower and big expensive plugins like Resharper to keep up.
I have kept the monster of Visual Studio off my ageing Vista era laptop for some time. Sharp Develop is an FOSS IDE that fills that gap nicely. Microsoft do offer Express versions which are good but they are rather frustrating if you have used the full versions!
Anyway Microsoft also produce Python Tools for Visual Studio which can be run on top of the free Visual Studio Shell. PTVS is also free and open source. It supports various versions of Python - not just IronPython (I am currently using it for PyGame with CPython 2.6.6). The code completion is pretty good and, surprisingly, it is not too resource demanding on my ol' Dell Inspiron 1501! It has a long list of features including refactoring, debugging, Django, REPL. Also comes with some extras for Excel and the Xbox Kinect.
I jump around editors quite a lot but I think will hang around PTVS for a good while.