I agree completely - contingent on getting good roommates of course.
1. Keeps you sane having other people about.
2. Means you're in a big place. Staying and working in a studio would be claustrophobic.
3. You will probably meet other people.
4. It's loads cheaper...
Course, if the flatmates aren't the right people then it would be hell on earth.
You should probably be upfront if you're planning on working from home - wouldn't suit everyone.
If you post that you're looking for roommates here I expect you will find some. Or http://sfbay.craigslist.org/sfc/roo/