I commute regularly on bikes that would cost $2,000-4,000 to replace. I park my bikes outside my office in a fairly safe location with a video cam and building security officers, and I lock them with a Kryptonite NY U-lock and cable. If one of my bikes gets stolen, so be it. I commute year-round about 30+ miles round trip and I don't want to ride that far on a beater bike.