It has HDR (I didn't even know what this was until you brought it up. lol) through another program called Yafray. Yafray is open source also, I think. (Free. Yay. lol) and it is more commonly being used in tandem with Blender to produce the most photorealistic pics. Most people now are modelling with Blender and using Yafray for the rendering if they are making a pic or animation that they Really want to look realistic.
Right now, I'm just getting the blender part down. It has a pretty powerful internal renderer also, so I'm getting everything I need out of it at the moment. Once I get Blender down, then I'll add on the Yafray and see what I can get out of it.
Here is a gallery that shows, pretty well, the difference between Blender and Yafray work.
http://blender3d.org/cms/Archive.179.0.html