Blender 2.48 includes all the work done on the Blender Game Engine and the Apricot Open Game "Yo Frankie!", with much better functioning game logic editing, character animation, and Blender Material based real-time shaders. And as last minute surprise a Bullet physics update with Softbody support.

Also in this release; Windows 64 bits support, Grease Pencil for sketching annotations,  Sun/Sky/Atmosphere rendering, new modifiers, and an improved text editor with Python API support. And last but not least, an enormous list of open bug reports were handled.

Blender 2.48a update:

A couple of important bugfixes has been done in Blender since the release, especially for using the Game Engine and GLSL. Read more here.