then only one that was my fault was just a floppy - I installed a new psu, and when plugging in the floppy's power molex, accidentally only plugged it into three of the pins instead of 4.  Booted up, lots of sparks and the wires just seemed to start burning, kinda like in movies when they light a fuse and it just takes off.  It started heading back to my power supply, but luckily I got to it before it managed to hit the actual supply.  My computer smelt like burnt rubber (since the wires were insulated) for weeks.  Luckily I just had to wrap up the ruined cable in electrical tape, and the others still work fine.  
I've had a couple hd's and a cpu fan die, but those weren't my fault.