Craving fish and chips.
I live in San Mateo, but willing to travel when I get the craving, and I spend lots of time in the city. I have yet to be impressed outside of England. Yes, Ive searched around, no I didnt find much.
I like Picadilly's, Old Chelsea, and O'Reilly's, but wolfe is right that some idea of what you've hated and thought passable would be helpful.
In San Francisco, the Pig and Whistle makes a respectable F&C. Their cornish pasties are decent too as are the Bangers& mash.
The Irish Bank in downtown SF does a good job with their F&C.
10 Mark Lane (off Bush St., between Grant & Kearny)
My absolute favorite (at least of late) has been the New Zealander in Alameda. Great beer batter type coating with wonderfully, light, fresh fish.
1400 Webster St, Alameda, CA 94501