For anyone applying to Birks - I will be one of many people to give you a heads up about the Uni's (in)famous 'Cardiac Hill' that goes from Birks to the campus. As the name suggests, it's quite a steep hill that will probably knock your breath out a bit and might make you sweat in the summer. It's definitely hard to get used to the first few weeks/months, but later on you don't really care. Otherwise Birks is pretty good and one of the newest and most popular accommodation blocks. It's around a 20-25 minute walk from the high street, and it's a 10-15 minute walk from the Forum (main campus building) depending on how fast you walk. Basically everything on campus is within 15-20 minutes from Birks.
Lafrowda is another popular choice and it's a bit closer to campus (and obviously doesn't have the hill). It's also right by the uni nightclub. The walk to city center is pretty much the same I think.