Hey skorlange,
I also got full funding + stipend from Madison, and it was tempting, believe me. Instead, I took zero funding at Berkeley, and I'm very happy with that decision (I graduate next month). I can't get into my old profile, but check out my old posts on costs, etc. under state_school'10. We have somewhat similar results, it looks like.
GSPP does a terrible job advertising this fact, but the program costs much, much less than the sticker price. After the first year, all domestic students get in-state tuition. If you're willing to work 15-22 hours a week as a teaching assistant, it is virtually guaranteed you can get full UC tuition remission, plus a stipend of about $1500/month. It isn't like Michigan, where a few people here and there get it; every single one of my classmates that wanted a position got one (maybe one or two won't admit rejection, but like 75% of us get positions along the way, and I think about half work all four semesters).
That leaves a few thousand per semester of the professional program fees. Housing is expensive, but with roommates you can bring it down to $800 a month. Bottom line, I would anticipate a cost more like $20-$40k max for the two years. I worked all four semesters, and it's definitely doable. I also got involved with a variety of other activities, and still have time to spend with my wife so it doesn't mean 80 hour weeks. More like 50/60s during midterms and finals.
I'm happy to chat more, and set up a call if you want. And keep negotiating with the financial aid, I regret giving up too soon. You might be able to get $5-10k, but even if you don't, you should still consider it affordable.
Andrew (akndrew at gmail)
