Gavin - seems like a reasonable idea.

Bitcoin would still have all the advantages of being decentralized (no central server, no office to raid and shut down. etc), but gets the added advantages of a core organization to guide it. Perhaps the core organization will get destroyed by the evil powers, but I'm not sure that'd be incredibly damaging to Bitcoin as a protocol. The community would just grow a new command center when the old was destroyed.

The main danger is if the community trusts such an organization too much.  For example- if everyone assumed the client version put out by the organization was trustworthy, then there is serious danger. A group as you propose should probably exist, but the community should remain skeptical of it, and always constructively critical.