In Canada, Waterloo is head and shoulders above the rest for almost anything. Ian Goldberg teaches there now, so there's at least one world-class security researcher. I believe there are plenty of startups in the area, but I don't have first-hand knowledge. I can tell you that a Waterloo degree is looked on very favorably at Microsoft, Google, and Yahoo.
In Vancouver, your picks are UBC or Simon Fraser University. I don't know enough about their grad programs to say anything useful, but I know SFU has a very good undergrad degree, and they really mentor their students to be entrepreneurs. There is a startup scene in Vancouver but it's a bit lightweight, with a few notable exceptions.
I had no idea that Waterloo was so into security research. I'm pleasantly surprised to see that some of the people in the department help develop OTR, which I've been using for just over a year (it was especially comforting while I was studying in China). As it stands now, Waterloo is at the top of my list of places I'll apply for grad school. Thanks for the great recommendation!
Keep in mind that a lot of UBC graduate students actually come from Waterloo. While Waterloo (and maybe SFU) have a good/strong CS department, they're strong in undergraduate.
In Vancouver, your picks are UBC or Simon Fraser University. I don't know enough about their grad programs to say anything useful, but I know SFU has a very good undergrad degree, and they really mentor their students to be entrepreneurs. There is a startup scene in Vancouver but it's a bit lightweight, with a few notable exceptions.