Cyclists need to use what President Bush calls "straterjurey" If a bike is going to be left on a public street in a big city for more than a few minutes, you need a "beater" bike that is too ugly to steal. Under the ugly paint, it can have Reynolds or Columbus steel, but it needs to be ugly.
Put a two pound u-lock around the front wheel and the frame. Put a five pound u-lock around the rear wheel and a beefy pole that is set in concrete. Park next to a shiny new Cannondale that is locked with a $5 cable lock. Which bike is the crook gonna take?