yeah, it's a big hill - but it's a big hill with a great view, and a big hill that's actually used by the community for a number of different uses.
when it's nice out you will always find people on the hill, playing frisbee, studying, napping etc.
for me, it doesn't get much better than sitting towards the top of flagstaff hill in the summer and taking in the view of oakland in front of you. as others mentioned, once or twice a week in the summer they put up a big screen and show movies on the hill.
if my life was an indie romantic-comedy, flagstaff hill would be the spot where the quirky, beautiful record store worker realizes she loves me and we first kiss.