A few interesting notes are coming out of this. They're trying to reduce the confusion that arose from having too many versions of Vista pushed at users, so they're stripping the message down: for most people, they are pushing either "Home Premium" (with the Aero interface and all the Media Center goodies), or "Professional". Professional is specifically a complete superset of Home Premium, rather than being the annoyingly overlapping sets they were in Vista. Professional will have some useful features for home office use, such as remote desktop hosting capability, but Home Premium is really what they're pushing for all normal users.
"Ultimate" will still exist -- essentially a single-user version of the "Enterprise" version -- but they're going to softpedal it as irrelevant to the average user, since it was more trouble than it was worth for Vista.
So (you ask) if there is a "Home Premium", what the heck happened to "Home Basic"? That exists, too -- but will not be available in the US. It'll be a little stripped-down in terms of UI, and only available to emerging markets. (Which means it will take approximately ten minutes before it is also available in the US. It'll be interesting to see how the pricing comes out on eBay.)
And there will also be a "Starter Edition", designed for netbooks, which can apparently be described as "Windows Sucking Edition" -- it will have an artificial limits placed on it, so that it can only run three apps at a time. This appears to have the sole purpose of convincing people that they *actually* need to buy Home Premium instead, although in fact it might suffice for a true low-end netbook. Mostly, it helps convince me that Windows is a poor choice for a true netbook, and you really ought to just install Linux instead. Which, in general, is looking like a more and more plausible option these days. (I'm seriously considering a Dell Mini 12 with Ubuntu, as possibly my perfect netbook...)