I'm in my first year of a PhD in Roc, I can give some details.
Re weather: it's not as bad as everyone says. Yes, snow, yes, lots of overcast days. I personally can't imagine picking a school based on weather. Then again, I'm from Toronto, so the snow/cold doesn't faze me at all.
Re needing a car. Everyone says that, and there's truth to it. I don't have a car, one of the few, and the ONLY one in my department. I live close to campus, and I bike in 5 min, through all weather. Love it. Groceries: big basket, and I bike 10 min to the local grocery store. Sometimes bum rides wtih colleagues. As a "man" in a car culture, not having a car seems to have the biggest impact on dating. Again, I've had no problems with that, though there's a real stigma against being car-less. F%cked up, but I deal. There are others, and it's worth finding out who they are and feeling like you're part of a likeminded group.
My rent: 650, plus 70/month utilities, for a fantastic 2 bedroom. I pay more than my fellow students, but I don't have car expenses, and I go out less becasue I'm at least 10 years older than them. I'm also not in the 'hip' neighborhoods, like Park ave, etc.
Note that you can live in a cooler neighborhood, car free, and use the UR (assuming UR) free bus system. It's route is limited, but it can easily be done. Bus runs once/hr, till 11pm ish. Worth looking up. That will put you in a lovely niegborhood, walking distance to a lot, but still need to bike/drive/bus to get groceries.
I came from a larger city, and I really felt the change to small city life. It was hard, I was used to living in the thick of downtown craziness, and loved it. But I'm getting used to it, after my first semester passed, which was brutal.
Can't speak about buying houses/condos, though some grads do, cause it's so cheap, esp those with partners.
Happy to answer more questions, if I can help.
david