re: Office 2013 Won't Run On Windows XP, Vista
@PJS880, if someone can't be bothered to upgrade from a 13 year old OS, I don't know what to tell you. People accustomed to taking their horse for replacement shoes could have used your same argument against the advent of automobiles.
I'm an advocate of OpenOffice myself, but I don't really share your reasoning. I see this move as a means to finally give people the incentive necessary to upgrade an OS to one that's more suitable for content of the present. Otherwise, Microsoft would have to staff a significantly sized team of people to constantly patch, upgrade, and support this new software on an archaic OS.
Granted, I'm focusing on XP in this reply as opposed to Vista. The number of XP systems still operating in the wild is mind blowing. Without measures like these, I fear we would be stuck with the old guard for far too long.
On an final note, perhaps you will agree with me on this; The better option may be, assuming the user is savvy enough to do so, just use Ubuntu with the OpenOffice Suite. If the user is not, then upgrade the OS for $40.00 (cost of Windows XP -> Windows 8) and be done with it.