Hinata on Van Ness is omekase (chef's choice) and is among the best sushi I've had outside Japan. It'll set you back at least $90 (prix fixe, more if you drink the delicious sake), abd requires a reservation, but you'll be synced with two other couples if you sit at the chef's counter where you will get a detailed description of exactly what you're eating, why it's interesting, and what to look for.

Schedule your reservation to start before 7 and ask to sit at the Chef's counter with Dave (he's the owner, in his twenties and quite knowledgeable).

If you like Hawaiian/Asian fusion, for about the same price range, there's Liholiho in Lower Nob Hill. Liholiho has blown up for a year, so get there at 4:30 on a weekday to make sure you get a seat in the first wave. Otherwise, reservations are a 4-week wait (last I checked).

You can get good healthy vegetarian at just about any restaurant in SF (minus steakhouses and shabu shabu). For a quick delicious vegetarian lunch, check out Plant in the FiDi.

EDIT: typos, readability.