I went to Berkeley (graduated in 08 so not too long ago), and had/have lots of friends that love in SF now. I always loved both Russian Hill and Nob HIll areas as both were nicer neighborhoody areas with cute little restaurants and shops. I also really liked the Marina district area which is more of a younger crowd if thats what your looking for. The Marina area is really awesome because you are close to a dog friendly beach area that has this really nice long paved path for biking, roller blading (you’d e surprised how many people roller blade out there!), or running and I belive it takes you all the way under the Golden gate bridge. The Castro is cool, but a little far away from the downtown area and from what I remember, the Mission area was a liiiiiittle sketchy. My top pics are defntiely Russian Hill, Nob Hill, or Marina District! Best of luck and good luck with the hills! Your calves are going to be sore!