they're all GREAT and prestigious programs. so u really setting yourself up for a great future going to any of those schools.
but UCSF and USC are more established than UCSD right now b/c UCSD is fairly still new and has not been accredited yet (they will this year i think).
UCSF is arguably the #1 pharmacy school right now but that's b/c every graduate program of UCSF is ranked top 3 worldwide--medicine, dentistry, doctorate... so u can't go wrong with UCSF.
USC is more geared towards retail i believe b/c 50% of retail pharmacists in socal are from USC. and they're known for their networking.
UCSD curriculum is very tough as they are integrated somewhat with the school of medicine. and i think they're gearing their program more towards UCSF and more clinical. eventually they'll be one of the top pharmacy schools.
ultimately, u can't really go wrong with any school. good luck