You're talking about re-branding. It can be quite a challenge - or a great move. Just make sure, first of all, that the new brand is a LOT better, because if any technical errors creep in you can have a very rough time. If it's a technically precise launch, all 301s working with no mess, then it can be a totally smooth move with Google.
I'd say the biggest issue I keep seeing in this kind of situation is changing all the absolute internal links rather than depending on the 301 redirect.