Where are you coming from and what to study?
I'm at Otago. It's pretty sweet, good atmosphere, generally a bloody good school (#1 ranked in NZ), really good for what I'm doing, but as you probably know these choices often come down to what you wanna study.
As for riding, yea Canterbury is closer to a lot more hills. BUT, there is a huge skier/snowboarder community in Dunedin (plenty of student flats with jib set ups, comps in town etc). Queenstown and Wanaka are where you ride from Dunedin, they are 3-3.5 hours drive away. Between these two towns you have 5 hills to ride at: Coronet peak - great fun field, close to queenstown, awesome snowmaking and base facilities, really fun freeriding, kickerspots, good lifts, ok park; Remarkables, a little further from queenstown, gnarly freeriding (and super mellow terrain too), really good park, and the Stash, usually pretty good snow too. Closer to wanaka is cardrona - big area, good lifts, big base facilities, good park and pipe (like really good usually), but other than that most of the terrain is pretty mellow; Snowpark - across the valley from cardrona, all park, world class, the place to be for the show ponies haha, nah its all good. And then there is Treble cone - ages from queenstown but close to wanaka, big, reliable snow, all freeriding, but super expensive, and the top lift is new but just a fixed grip.
Dunedin may be a bit of a drive from the snow, but if you have no class on friday afternoons then that'll help heaps, and there are heaps of people around to carpool/share accom etc. Quite a few good shops in dunedin too to get gear sorted out.