So I was just curious, Skyrim's developers, Bethesda Softworks, do they use Maya or 3DS Max for their modeling? Or do they have their own program? Anyone know?
Also what scripting/animation programs?

Overall they use a heavily modified Gamebryo 2.2 engine for the mesh handling. As far as I know they used 3ds Max for Skyrim since they used it for previous games. For animation, they are now using Havok (2010.2 Update) but probably with the integration with max. In previous games they used Gamebryo for export. In theory they could use Maya as Gamebryo had exporters for that.

Scripting is something they wrote in-house as far as I know.

Don't forget sculpting programs like Mudbox, just seen the 'making off' I always thought they where using Zbrush but the grey backdrop reminds me of when I tried Mudbox (although that was a few years back)

The only thing you can be absolutely sure of is that they are not using their own software to create models.

Like the previous posters said, they are most likely using 3D Max for hardsurface modelling and Mudbox or ZBrush for sculpting. They used 3D Max for Oblivion and Morrowind.

Wow, I can only imagine all the effort put into modeling, animating, scripting, EVERYTHING that's in Skyrim. So much content.

Devs tend to use Maya for animation, I think? Not sure. I've only very recently set foot into modeling, and I've been using Lightwave 3D exclusively; it's the only app that has an exporter for DAII. I've got both 3DS Max and Maya (Autodesk offer them to students for free, no pirating here!), though, so I want to try some things with Skyrim.

I believe they used 3dsmax in the past, and probably still are.