I had two original PS2s that both failed, my slim-line was still working last time I used it - but it's been a few years since I last connected it up.
Most of my old consoles still work (those I've held onto at least), but the more complex the consoles become the higher the failure rate climbs. My SNES still functions, but it's sound chip seems to have died. I sold my MegaDrive II, but that was in great condition. My first N64 was fried by lightning (I won't hold Nintendo responsible for that one), it's replacement still works perfectly (controllers held up well too). Sold my Gamecube, but that was working when I did. My Xbox crystal still works perfectly. My launch 360 got the 3 red lights twice, but I traded that in after the second repair and got a super elite - which so far has been fine (hope it keeps going strong). All my gameboys still work including the original model. My Wii probably works but is never used.