Photo Editing Software

RawTherapee is great free alternative to Lightroom and in my experience is a hell of a lot faster.

3D Modeling Software

I personally use 3DSMAX, but if I've also heard great things about Blender (including that its free).

HDR Panorama Sticher

I use PTGUI Pro, which is definitely one of the best stichers out there. The free alternative is Hugin, which I haven't had any luck with.

Free 3D Models

This is one you just have to search for. There are countless sites out there that have free models; Turbosquid, CadNav, CGTrader, and Sketchfab to name a few.