first off, just know that if a thief wants your bike, it doesn't really matter what kind of lock(s) you have. sure, replacing your QR's with bolts might work but then again, most thieves in LA carry tools. theft in LA is crazy these days, as people have had their bikes stolen from inside their apartment. it's mostly the fixed gear bikes that are targeted, though.
second, i have found the U-lock + cable to be most practical. actually i usually just lock up with a U lock through the rear wheel and seat stay, but if i was really worried, i'd loop a cable through the front. i mainly ride for sport/fun and not for utility but if i really needed a bike to get around town on, i'd get the crappiest looking beater.