My guess is that most students living in Hyde Park will be married, have families, or be U of C undergrad alumni. That's the impression that I got at the admit weekend, where I heard that about 10-15% of students live in Hyde Park. I think living in Hyde Park actually could have a number of advantages...but if you are the type of person who will be going to the north side to go bar hopping and drinking at least 2 or 3 nights a week, I think it would just be impossible to live in Hyde Park. That would be a 30-40 dollars cab ride 3 nights a week. Even split between two people, you might as well just take that 500 bucks a month and use it to get a place downtown. HP is a beautiful old Chicago neighborhood though, and if you like a more quiet lifestyle and don't mind a 15 minute train ride downtown on the weekends to meet your study groups at Gleacher Center, I think it's a great option. Plus, HP has the Original Pancake House, which is the best and cheapest place to get Sunday brunch in the city
Edit: I should add that I am planning on living in Hyde Park, although also sort of considering the south Loop, and yes I am married but have no children.