If anything, HD+ should be 1440p. I hate when Apple tricks the public with terms like this. 1080p is nothing new or special.
I don't understand why everyone's complaining about the name. They have to call it something, if only to distinguish the 720p and 1080p offerings that will certainly coexist for awhile in the iTunes store.
You have to remember that Apple is in the business of selling hardware, and that's where these distinctions are most important to them. When you buy a 720p show or movie currently, it shows up in iTunes as "HD-SD", meaning there's a 480p version included solely for compatibility with non-HD Apple devices like older iPods and iPhones. When "HD+" is available, they'll still have to support current 720p-only devices like the iPad 1, iPhone 4 and Apple TV 2. So presumably in iTunes a 1080p movie would be marked "HD+HD-SD" or something like that to indicate all three formats are available, depending on which Apple device is syncing or streaming it. If they just call it "HD" the distinction would be lost which to me would indicate that they won't support 720p-only devices anymore (even though they're still selling them even now?) -- not a good thing. So, as an owner of an Apple TV v1, iPhone 4, and (hopefully) a soon-to-come Retina iPad 2, I'm glad to hear it's not just being folded into the "HD" category.