What additional rights will legalizing gay marriage in Canada convey to gay couples?

Per this story from the Washington Post

Same-Sex Marriage Endorsed In Canada
Government Will Act to Change Law

http://www.washingtonpost.com/wp-dyn/articles/A7547-2003Jun17.html

I am not at all familar with Canadian law or the status of unmarried Canadian partners. What specific bundle(s) of rights will be granted to gay Canadian men and women with this new law that they do not currently have?