I've just got back to my computer, and have enabled most of the comments offered.
I have capriciously decided not to allow yet another category: comments including the grammatical error "We must respect he who is the King of Tonga". We do not, in English, say "we must respect he [nominative]"; we say "We must respect him [accusative]". A curious idea seems to be growing up that whenever the relative pronoun "who" is used, it has to be preceded by a nominative. It most certainly doesn't. This is the same sort of error as using the nominative for the second of two linked names: "He spoke to Theodore and I". We do not in English say "He spoke to I"; we say "He spoke to me". So: "He spoke to Theodore and me".
I once heard a colleague refer to "Paul and I's study".
A less spectacularly horrible usage which is getting common is to make genitive only the second of two linked names. "Michael and Anne's house" is incorrect. It would imply that we were talking about two objects: (1) Michael; and (2) Anne's house. If we are talking about a house which belongs to both Michael and Anne, the correct form is "Michael's and Anne's house".
The correct thing for that colleague (who, incidentally, was a Wykehamist, heaven help us) to have said would have been: "Paul's and my study".
So there. Dixi.