If I had a pick of what sushi place to eat in the valley, hands down it would be Sakana. This might just be my tastes but their sashimi, sushi, and dishes are fantastic. I'm not a big fan of the fancy rolls but they seem to have a good selection and my friends enjoy them quite a bit.
My favorite items are the tuna/salmon sashimi plate (big, thick pieces of fish!), tuna tataki salad, the hamachi-kama (they make it the best here by far), and the unagi. Can't ever say enough good things about this place! :)
Also, did I mention the sushi chef is the best?