now you can user the new Blender rendering of the new 2.5 version (you are not obliged to use the whole prog :)
it win a 10 factor speedy!
http://www.blender.org/development/release-logs/blender-250/ray-tracing-optimization/
http://www.blender.org/development/release-logs/blender-250/volume-rendering/
http://www.blender.org/development/release-logs/blender-250/other-rendering-features/
etc...

And with the nodes system you have infinite possibilities of rendering! (old interface here not the 2.5! )