But Waterloo isn't a great city to live in. Especially for young professionals, Waterloo is not nearly as exciting as Toronto, Montreal, Vancouver.
I think Kitchener-Waterloo (~300k people) punches above its weight. It definitely feels like a small city, but there are still things to do. Plus Toronto is 1.5 hours away on a Greyhound bus for about $15. ;)
Waterloo demographically compares to Raleigh. I make no judgement about relative merits of living there, but just in size it's small.
[edit] just Raleigh mind you, The Triangle is much bigger than that.