If you already have a Xbox live account, it will become a GOld account oce you get a an xbox360.
And as for eeproms and whatnot, I say just get on. There are going to have a lot more measures to detect mods/changes this time around, and we have no idea what they are. So you might as well just get on live and enjoy it right away, since it could be a while, or a long time before we know what those measures are.