Have a look at the MWDEU entry, it says it much better than I could:

http://books.google.ca/books?id=2yJusP0vrdgC&lpg=PA877&vq=subjunctive&dq=merriam%20websters%20dictionary%20of%20english%20usage&pg=PA607#v=onepage&q&f=false

It's a common British regionalism.

Actually I meant to write "Caesar's murder"

Apostrophe-s is used for things other than possession.

Caesar's murders - object genitive (ie, someone murdered Caesar)
men's shirts - genitive of purpose (shirts for men)
Terry Pratchett's latest book - genitive of origin (the latest book by Pratchett)
a year's wages - descriptive or classifying genitive

porsche, I agree that "writing books" functions as a noun. But "writing" is not a noun. Call it a gerund or "-ing" form or participle, but it's not a noun. But many usage guides say you must use a possessive in front a gerund, because a gerund is a noun. This is clearly mistaken. If they mean that when gerunds have objects, as in "writing books", that the entire "gerund phrase" functions as a noun, then that's what they should say.

According to The American Heritage Book of English Usage, it is standard English.
http://languagelog.ldc.upenn.edu/nll/?p=3038

I am not the same Goofy as the Goofy who posted those two links. When I say "evidence" I'm talking about how good writers actually write. Anyone can make a website stating their opinion. But how can any consideration of the situation ignore actual usage?

Perfect Pedant:
Which evidence are you referring to? The evidence provided by MWDEU shows that both "was" and "were" are standard English. Lots of people here have stated their opinions, but I haven't seen much evidence that only "were" is standard.

willy wonka: I don't think you'll find any English usage book, no matter how prescriptive, that says "If I lived in Paris, I would visit the Eiffel Tower." is not correct.

The MWDEU discusses the subjunctive in detail in the entry I linked to way back at the beginning of this thread:
http://books.google.ca/books?id=2yJusP0vrdgC&lpg=PA877&vq=subjunctive&dq=merriam%20websters%20dictionary%20of%20english%20usage&pg=PA876#v=onepage&q&f=false