I have had hard drives fail, just did a complete reinstall of my daughter's computer this past weekend. CD-roms have decided not to read or spin, floppy drives refuse to see that the floppy in them is already formated. LCD's have had their backlight burn out, had pixels die, CRTs that went all shades of only one color. Mice and keyboards untold have given up the ghost at the worst possible moments. Adapter plugs on laptops have had better things to do than move the charge from the plug to the battery. Motherboards, laptop and desktop, have blown in one way or another and are taking up space on my rack. Raid cards, video cards, modems, usb and firewire cards have stopped working.
I think that about covers my tales of woe.