I would assume you'd try to go where the best talent pool is, although the cost of living and maintaining a business would be a big factor too. Like others have said, Vancouver sounds like it has a strong base, but it's pretty expensive. So is Toronto, I have no idea about the other major cities. I remember EA had their offices in downtown Van, but I hadn't seen it the past few years. It turns out they moved it to Burnaby, a suburb. I guess they have more space for an actual campus, rather than renting a ton of expensive downtown office space.
Toronto's closer to the US. Calgary is oil & gas / cowboy country. I'd stick with T.O (after all, the NBA did)
Calgary is nothing like Houston, Houston being a way bigger city. Also Vancouver is a very major city, more important than Dallas or any cities in Texas excluding Houston. Toronto - Most diverse city in the world, close to the US. A lot of Jamaicain, Turkish, Chinese people. The city can be compared with Chicago. Montreal - Hottest women in Canada, high Haitian population so it makes to city pretty dangerous and yes the official language is french but people speak also a lot of english in Montreal, you can live and work perfectly there if you only speak english.
