Since the Saturn havent had problems pretty much but whole history
NES - bought it for 5 dollars knowing there were problems reading the cartridges, went on and off in terms of reading them.
Sega Mega Drive - No problems for most of it until someone stepped on the power plug and then you had to put heavy things on it to make it work... I still want a new one for this reason :(
PS1 1st one - worked perfectly fine but sold it for a N64
ps1 2nd one - had problems with the av cable, had to unplug it and then plug it back in again. The problem was it went all greeny and odd. Had slight disk reading issues.
N64 - no problems
Ps2 - no problems
Game Cube - No problems
360 - after plugging in and out hdmi cable it broke. Component works fine though still playing HD. :)
PS3 - freezes a fair bit when playing co-op.
Wii - no problems