My old PS1 lost it's ability to read discs properly after the peg that depressed the engage button for the laser gave out. I fixed that with the help of a cocktail stick and some super glue.

My old PS2 lost it's ability to read discs but it was actually just CD's it stopped reading. Thankfully I knew and still do know how to repair these things and simply stripping the console down to clean it and then re-tuning the laser (the white cog at the back of the disc drive which you can see when you strip it down does this, theres 2 settings on there that work for both DVD and CD, you just need to fire it up and test with both dvd and cd for each tooth of the cog until you find the right one).

My 20GB Xbox 360 was killed by Gears 3, it got a fatal red ring of death that I had no hope of fixing, considering the age and limited space on the disc drive.... I gave it a viking funeral and picked up a new 250GB slimline black one still in operation today

Other than that, I've not really killed any consoles aside from my first DS, that died when the hinge literally snapped. The hinges were infamous on the original DS for being the weak link it was to do with the plastic used in the casing being really brittle.