Business dinner Palo Alto
There's really nothing that's "too fancy" in Palo Alto, so you're safe there. Lavanda is a pretty staid choice with an extensive wine list. Zibibbo is another solid choice with a pleasant patio. Evvia is greek so doesn't really fit into your california requirement, but oft recommended here.
On California avenue (much quieter than University) there's Bistro Elan. I went there for lunch a few years back and it was nice enough, but perhaps others have more recent feedback.
Tamarine has really good food with a relaxed environment where you can actually hear each other talk. Tamarine is "contemporary Vietnamese," but given the Asian population in California, I actually think it is classic California.
I second Bistro Elan based on the foie gras, but the tables are spaced close together, so you won't get as much privacy.