To be certain I am no fan of MS and prefer Linux whenever possible. I have a number of machines running Win7 and so far it would appear to be the best version of a bad operating system yet. The problem with all of this is simple: The more secure an operating system is the more demanding it is on the user and the less freedom one appears to have. Assuming you have the ability to give yourself administrator privileges in XP, Vista or 7 you can give yourself all the freedom you could want, possibly shooting yourself in the foot by doing so, but the possibility is there. In Vista you could turn off the "Are you sure..." messages, but you had to know how and it isn't really trivial to do so. That is the case with all operating systems that have a certain degree of security. I have spent hours studying a Windows 7 administrator's handbook to learn how to use the management console and snap-ins, set networking allowances, tweak the user interface, etc. I don't have my black belt in 7 yet, but I'm working on it because I have users that need to know how to get along with it. Most people rightfully don't want to spend that much time on a stupid operating system, but computers and networking, Internet and intranet are very complicated systems. It ain't really fun, but it's life on the planet.
Regarding the original post, the backup-space problem is a known bug and occurs with drives that are larger than a certain size (I don't remember how large). I personally would never trust Steve Balmer to back up my data.