To be honest, the areas that students are likely to live in, and go to, are not dangerous areas. Why would students get a house in Gipton? Leeds is no worse than any other major cities.. there's places where you don't go, but they tend to be the places you don't *need* to go to, and would have no reason for going there.
Basically, just use common sense. Don't go out at night on your own, especially if you're a girl.
LOCK YOUR DOOR. The area most students live in - Hyde Park, Headingley - are one of the most burgled areas in England, and its because burglars just walk in, take stuff, and walk out again. Just be sensible.
And yeah, don't walk through Hyde Park on your own at night. Its fine during the day though, just full of students playing footy or laying around.