I came across an interesting posting by Matthias Kaiserwerth, the director of the IBM Zurich Research Lab, entitled "who do you work for?". In this posting Matthias raises the dilemma, that it is much easier to identify with a smaller organization, sometimes until the level of a single project or department, rather than to identify with a big corporate, or any division of it.
I certainly agree, in the past, the department I managed had a logo, and I found that people identified much easier with this department, relative to the lab, division, or IBM. While this had a great contribution to the people's motivation and "unit pride", it was not popular in the environment (which I never thought it is a strong consideration). Creating excellence requires to have identification with a goal, it is much easier to identified with goals that one feels partner in, and not of some abstract entities.