The link below is a must read article to partially answer some of the questions discussed here.
http://www.macleans.ca/business/markets/article.jsp?content=20080924_24660_24660
First-time buyers have been drawn into the housing market with "no money down" mortgages and up to 40 years to pay them back.
When they add mortgage insurance and closing costs (such as land transfer taxes) to their debt, they already owe more than 100 per cent of the property value.
美国影响初现:加国银行提高按揭利率