I go to the beginning or end of a sentence much more often then to the beginning or end of the document, so for me, Window's setup is more logical.
I type a lot and do not find that I navigate to the start or end of a sentence often. Usually, when I do, I’m on a single line field and the up and down arrow keys are much more readily to hand.
Oh, and Control-Home or Control-End doesn’t work in all of *Microsoft’s* own applications. In Publisher, for example, Control-End moves you to the end of the text field (and if you’re not in a text field it either doesn’t work or PUTS you in a text field), not to the end of the document. In Access, it doesn’t move the page at all, it *immediately* takes you to the last field in the last record in the file. In PowerPoint, it works like Publisher, and it doesn’t work at ALL in Visio.