Do BIOS Upgrades Really Matter?

inkfox asks: "It seems that whenever one buys a motherboard, there's already a BIOS upgrade available by the time you get your hands on it, usually dealing with some degenerate hardware behavior. Given that Linux and Windows 2000/XP replace all BIOS routines once loaded, do these upgrades really matter? If a system is successfully booting, is a BIOS upgrade more a risk than it is preventive maintenance?" This may be true, but what if you are running an OS that depends on the BIOS? If the BIOS is replaced by a specific OS, then BIOS upgrades can't really hurt anything, can they?