Always use relative path

Blender 2.63a

When working cross platform,it’s important to have all blend files use relative path. That every other files linked into the blend can be found in the path relate to it, with no OS specific mount point.
By doing

File->External Data->Make all path relative

And see the result message at the top of the screen if something went wrong. This way you can be sure that your blend will be opened in other OS fine, provide that you don’t change the folder structures.

This can be useful for archiving the project after you finish it, by storing the whole folder structures as is, you can move your project anywhere without losing links or external textures.