I would steer away from the hill district (At the top of the hill past trees hall). It tends to be a rougher area. I lived in South Oakland when I went to undergrad at Pitt and it was loud, dirty, and most of the housing wasn't kept up very well. I would never want to live there for grad school, or ever again. Now I live in the north side, which depending on where you live can be a little sketchy as well, but I've lived here since the summer and I love it. If you stick to the Mexican War Streets, you'll be fine. Other safe areas to pick from are Squirrel Hill and Shadyside, but Shadyside tends to be pretty pricey. There are plenty of suburbs that are nice and safe, but personally I enjoy the convenience of living close to campus and all of the entertainment on the north side. If you find a place, feel free to ask if it's in a safe area! I took the buses everywhere in college and I never really took them earlier than 0600- they tend to run until about 0230 and then pick up again around 0400-0500, although before 0600 the buses come infrequently.