QUICK and simple blurb on each of the UC campuses that would be wicked.
Berkeley: Oldest UC campus, Greek Revival architecture, top academic departments in most disciplines, Pac-10 sports - football on-campus, on a hill overlooking SF Bay Area/Golden Gate bridge, area accessible via public transport (BART), urban, "crunchy granola" vibe.
UCLA: Nice campus, top academics, Italian Renaissance architecture, Pac-10 sports - football not on-campus, L.A. glamour, better weather, better looking women, public transport an issue - more difficult getting around.
UC San Diego: Overlooks beach in La Jolla, top academics - esp. biological sciences, 60s modern architecture, confusing residential college system, not as much campus spirit - lack of major sports.
UC Santa Barbara: Campus overlooks beach in Santa Barbara, great academics - esp. physics, engineering, less commuterish feel than UCLA, Irvine and San Diego, Isla Vista party central
UC Davis: inland campus north of the Bay Area, not far from Sacramento, great academics - esp. veterinary, agricultural, bikes prevalent, college town, only UC (other than LA and Berk) with a football team.
Those are the campuses I would choose from for a visiting international.
UC Santa Cruz is smaller, beautiful wooded campus overlooking ocean in Santa Cruz, CA. (south of Bay Area), liberal vibe.
UC Irvine and Riverside are more commuter-type campuses but have great academics.