I know that I will be. Only one PC in my house has Vista, and we've been waiting for the "full version" of Vista (which is what we are calling 7) since Vista came out.
I do expect some businesses will transition to. Really, its the only way to get them out of their old software licenses: they kept XP to use their old software, and therefor most of the newer software won't run (or eventually won't run) on their systems, which will make businesses get into the mentality of never ugprading. By offering Enterpise and Ultimate with XPM, they can get businesses into an OS that will continue to support new software, which will mean that when a business is making the decision to upgrade, they won't be saying "well it doesn't work with our OS, can't use it."