A few more things to consider:
Again, Columbia's great, but you should not decide against UCSF due to concerns that it's funding, faculty, or academic quality might be compromised by the UC budget problems. In reality, UCSF will always have more many to spend on medical education, patient care, and research than most private schools (Columbia included), unless its Harvard with it's $10 billion endowment. That's because you'll always be receiving a fluctuating, though stably massive amount of funding from the millions of California taxpayers and NIH. If anything, UCSF's academic enterprise is really growing, as I imagine Columbia's is as well. A few examples:
-Last week, UCSF hired Dr. Arnold Kriegstein from Columbia (head of stem cell program) to become head of it's Stem Cell program. At least in this case, someone felt UC was offering enough money and other incentives to leave his private school.
http://medschool.ucsf.edu/news/news/042204_Kriegstein.aspx
-Last summer UCSF hired David Kessler the Dean of Yale School of Medicine and former FDA chief, to become it's new Dean.
-At least from these two cases, UCSF is still highly successful in recruting what it views as top faculty and leadership.
-Finally, UCSF is buidling the Mission Bay campus. MB is a 44 acre life sciences campus that's currently the largest medical and biotech construction effort going on in the country. It will double the size of UCSF's research and clinical capacity over the next ten years. It will include a dozen new research buildings (3 of which are completed), and a new hospital or two.
Again, Columbia is growing too. I don't know details but I know they did just construct and impressive new children's hospital. My point is just that UCSF is doing well also.
-I don't think the argument about diversity holds weight. You can't get more diverse than UCSF with the range it has in age, previous experience, educational background, etc. True, 80% of students are from CA, but CA is a big place and at Columbia the majority of students will also be from the east.
-Yes, Columbia is ivy league and has a more well known household name, but I think that's a terrible way to pick a med school. First, if you care about name dropping, Columbia is not Harvard or Yale which in my opinion are the only two universally recognized school names. You'd be surprised how many "regular" people or those in the west think "Columbia" is that country in South America or the space shuttle we tragically lost. Columbia University though a top university is not as well known as some might think. At least in northern CA going to what's known as "UC Med" is the bigger name. In the end what will matter most is how you're viewed in the medical profession, and there, both UCSF and Columbia are big enough names.
I suggest again that you base your decision on location, curriculum, and other personal factors. Visit both schools again if needed and talk to as many students as possible. Then go with your gut.