Windows 7
Mike Nash, one of the VPs in the Windows Product division at Microsoft had a recent blog post announcing the new name of the next generation Windows operating system. Looks like this will be one of the few times that the development code name will be the full release name.
Personally, I’m not sure why I have ever known the internal development name of a product from Microsoft. In reality, it should stay internal if you have good security measures in place as the only people that need to know the name are the developers and engineers working on the project.