As you have found out from the Apple website you cannot use your me address as a primary address, unless it was migrated from a mobile me account.
You don't have to use your primary address for anything, just ignore it. You can log into your various accounts that you use your ID for using either your primary for alternate address, simply use your alternate (me) address.
I wonder if this is a sign of hope: http://www.macrumors.com/2012/07/16/apple-rolling-out-icloud-com-email-addresses -with-ios-6-beta-3/
Apple will apparently be rolling out @icloud.com email addresses when iOS 6 launches. If you're new to iCloud, you get an @icloud.com. If you already have @me.com or @mac.com, you'll get a matching @iCloud.com address.
So none of us have been able to set our @me.com as our primary email address, because it says you can't use a MobileMe account as a primary email. So maybe we'll be able to use the @iCloud version as the primary email? But then I'm sure there are plenty of people (myself included) that prefer the brevity of "me" to "icloud", so... I dunno.
Or maybe having @mac, @me, and @icloud versions will just muck everything up further, and we're all screwed!