UC Davis & UC Santa Cruz ???

It really depends. If you are doing only undergrad degree, there won't be a substantial difference. However. if you are talking about post-grad degree. UCDavis is definitely the place to go.

For your information, I've just received 2007 US NEWS & WORLD REPORT ranking. Here is the information that may interest you.
UCBerkeley (21)
UCLA(26)
UCSD(38)
UCI(44)
UCD(47)
UCSB(47)
UCR(88)
UCSC(76)
UCSF doesn't count since it is a medical school.

Since I don't know which degree and subject you are planning to puruse, I cannot offer any definite and candid comments. However, let's say that you are interested in PhD in economics (that is my field, actually!) UCDavis is the place to go since it tries very hard to maintain a small class size to preserve needed interaction between students and profs. Berkeley is even more reputable than Davis too (again in economics) but the class size of the former tends to be larger than Davis.

Just a curious question (perhaps I am being nosy), why don't you think about schools on the east side of the US (like Boston or Washington DC). Boston College, Boston University, Georgetown, Johns Hopkins are pretty internationally reputable as well!

Hope this help! If you need further information. Just post it on the web and I will try my best to address your problem (because I am also applying for PhD programs in the US as well!) Good luck!

UC Davis
ranking is higher and more HK people knew.
UCD is better

Depends on what major. You can research more at website http://www.princetonreview.com/

According to US News, which publish a quite reputable US college ranking, Davis rank 47 and Santa Cruz rank 76. (http://www.usnews.com/usnews/rankguide/rghome.htm)

UC Davis has longer history, so more HK people knows. I will pick David, although the city Davis is very boring. I know it is not difficult to transfer between UCs despite the process is time consuming. Get into Davis and if u don't like it then transfer to other UCs, your earned credit and grades are transferable.

2006-10-26 01:03:46 補充：
Just tell HK people you are 加州大學. Besides Berkeley & UCLA they can't tell the difference.