Bitcoin is a trademark held by MtGox, on the dubious theory that "better they than someone else". There was some talk about them transferring this to the Foundation, but nothing came of it AFAIK.
So if the foundation still hasn't done anything about this, then shame on them. Bitcoin is then an asset in the bankrupt holdings of MtGox currently controlled by the courts of Japan.
"Bitcoin" is no longer protected and is within the public domain both in law and fact. Specifically, the word is not seen as a viable asset worth protecting by any specific government or court trustee within the scope of the current proceedings as that is not their focus. Likewise, I doubt anyone would be successful in the long term claiming ownership or exclusive use via a trade and/or service mark.
Scott-
You have a link to court ruling, invalidating the registered trademark?
This might be so, but it wasn't like that in the beginning, and that's when someone came up with the idea that they'd put down the cash to register it. MtGox managed to stop them. But this should have been done at inception by the foundation, not left open for whatever business entity to register.