My only bike is a beater. By this I mean it's old, the components are low-end, and the paint/decals are beat up/chipped/ugly.

I ride it because it's my only bike and it works great. If it didn't work, I would go buy something else. It does work, so I'm saved the hassle of finding a replacement.

I'm beginning to think of the potential theft loss not as "I lost $x dollars" but rather "I lost $X time to replacing this". I almost don't care, really, the cost of a replacement bicycle. It's more about how long I'm going to be out of commission and how long it'll take to get everything back configured right.