Another option is OpenB3D, which I coverted awhile back... http://www.glbasic.com/forum/index.php?topic=6982.msg56815#msg56815
Since then, AFAIK, OpenB3D has had quite a bit of development since then, so it would bring more to the table.
Since Blitz3D became open source, there are some interesting aproaches coming around. Hybrid/Blitz Hardwired is an example: a port for DX9-11 of the blitz3d sintax/compiler, adding shadows, physics, etc... Yep, win only, but likewise is being port for DX9-11, should be for OpenGL. A lot of work sure it is.
Another aproach will be irrlicht (i´m a little bit of a hater xD), but Urho is way ahead: shadows, physics, skeletal animation, and all advanced shit integrated in one place for good. Is the best free option I found, and I´ve been looking a while now.