I think that I'll give a try at the OGRE engine. My choice is due to several reasons:
1. I've followed the development of the engine for quite some time now and I like the continuity of the development.
2. I'm quite a hardcore C++ programmer and OGRE fits my style of programming although I wouldn't have chosen to use STL in any way.
3. When I included vertex- and pixelshaders into my engine, I've taken a deep look into the OGRE sources to see how they've managed to include the programmable pipeline. So, in some kind, OGRE has been an inspiration for me ;)
4. The framework seems to have a reasonable learning curve so that I can produce interesting results in short time.
5. There are exporters for almost all mayor graphic tools and a lot of image formats are supported.
6. There were some nice demos in the 1.0.0 demo package which showed some of the effects I need for my projects.
7. There's an animation system included.
8. There are several products that have been successfully finished.
There might be several other reasons but those are the strongest I have found (among the one that it would take me just too much time to do all that on my own)...