For the south bay area, here are some rates from the Cornish & Carey NoCal quarterly report
Asking Rates (NNN/per SF/per Month)
A historical perspective can be seen at here Note: I tried everyway I could think of to put this data in a table and to make the image display inline and could not make either happen. If someone knows how to make this happen please email it to me at dane "@" awrcorp "dot" com.
Office Space in San Francisco is a tricky. There's the downtown stuff for the lawyers and bankers and then the artsy stuff in the Mission. Here is what I could find out:
I don't know much about the East Bay but the rents are a lot cheaper. High Tech / Bio Tech guys tend to be in Emeryville, Downtown Oakland, Berkeley and farther out in Walnut Creek.
A lot of Software Startups are also near Oracle in Redwood Shores, Foster City and Redwood City. A lot of the office space around Oracle tends to be in the $20-$30 per square-foot range. It's nice stuff but kind of out of the way (e.g. not much to do or eat).
Check out this "Garry's San Francisco Guide to Where Your Startup Should Be"
http://maps.google.com/maps/ms?ie=UTF&msa=0&msid=111291639665197066699.00048b3c0d910bf1a232a It is an interactive map that shows you details about all the hot areas for startups in the bay area.
We just negotiated a lease for $1.25 for Class A space, furniture, great looking space and building, for $1.25 in Santa Clara, full service.
Update - we signed the lease and moved in. It's a killer space; we love it.