I asked
the same question recently (I'm also a first year MA student, going to Carleton) and decided on the Blackberry Bold 9700.
The reasons I decided to get a BB: I hate touch screens; BB is made for email and business; no professor at McMaster I knew had an iPhone, all had BB; I know a ton of ppl with BB so I'll be using BBM a lot; most of the apps have no appeal to me; and the whole iPhone 4 debacle had totally sullied my opinions of Apple.
I'm with Virgin (or, rather, I'm continuing my service with them), and I'm on their $50 a month plan which includes $500mg of data,150 talking minutes, free unlimited texting, free caller ID and call transfer, and free local evenings and weekends (starting at 7pm). That also includes no system access fees (which Bell, Rogers and Telus all have).
With some companies, once you sign up with a plan you're not free to modify it. With Virgin you can change to any of their plans (higher or lower) once a month for free.
As for using Skype, I'm not sure. Depending on how it works for mobiles, you may have to pay to use it to call. Otherwise, yes, long distance calling cards work.
I'm not sure how purchasing a phone/package would work for other provinces. For some companies they offer different plans in different provinces, and/or certain plans aren't available in certain provinces. You'll have to research that further.