There should be a set of default bindings available that you can load from the key binding interface.

I saved a set of bindings that incorporates most of the 'defaults' from the manual, but with a few customizations, like standard WASD movement, Q/E lean, shift to walk, etc.

Here is a download link for them. I hope it's a good site to use (free):

http://www36.zippyshare.com/v/6577010/file.html

No point in a "walk" key. You should ALWAYS be able to run in the game, always. Also while the lean buttons were more useful in Thief where you could inspect your surroundings without leaving the shadows or making any noise, and here stealth doesn't play nearly as big a role, they're still good to have.