Blender 2.68

• Many different mesh modelling tools were added and improved
• Cycles render performance was improved on Windows and on GPUs
• The motion tracker can now automate placement and choice of markers more with new tools
• Smoke rendering quality has been improved to reduce blockiness
• Particles can now be emitted from faces generated by modifiers that were not in the original mesh.
• Usability enhancements – improved weight painting tools, mask modifier for sequencer strips, 2D image paint more consistent with 3D painting, better key shortcuts display, quick enabling and disabling of multiple layers or visibility, etc.
• New addons – Texture Atlas to bake shadow and lightmaps for an entire scene, and Edit Linked Library for quick editing of linked assets

More on Blender.org.