I keep all the info on my bikes on the innerwebs cloud that's readily accessible anywhere and on my iphone. In addition, I can also spurt out the parts spec of each bike by memory - yeah I'm that obsessive.

And I'm going to use my U-lock and extension cable (for the front wheel) to lock up my bikes which range from a cheap folder to a pricey FS mtb, whether in the city or in the small town I live in.