I have a PlayStation 1, Xbox 360, Xbox one and a Gameboy Advance. I don't sell consoles away once I have bought them, I just like to keep them around. I still hook up my PlayStation 1 from time to time, as it has some really nostalgic games for me. All of the consoles I own function flawlessly.
I have PS1 and PS2 and I am pretty sure they both work, but I don't have a tv to find out. I pretty much stopped playing new games once the PS3 came out. Game companies just weren't making the kinds of games that I like to play anymore.
Every console I have still works. I currently have a Dreamcast, N64, NES, SNES, Sega Genesis, Xbox and Xbox 360. I'm tempted to get a PS1 because I keep seeing them at thrift shops and hear that their CD players actually sound really great for music. My favorite is definitely the Dreamcast. I didn't get it until the end of that console's lifespan but I probably play it the most nowadays. It's a totally underrated console in my opinion.
I guess I'm kind of cheating though since I had to replace parts in the NES to get it to work. It's also one of the more rare top loading models which is kinda cool.
I have a PS 2 that still works really well, and a GBA that still surprisingly turns on (!) but then turns off again after a few minutes. These two consoles have really defined my childhood and even if I grow old I don't think I can ever part with them. I'd probably just put them in a box so I could show them to my grandchildren years from now.
AS far as old school goes, I still have my dad's SNES that still works like a charm, I also have a N64, PS1 and PS2, and the Gameboy SP (Had the older GBA and GBC too but I think I gave them away). All of them still work like a charm and I still brush off the dust and play them every now and again. There's nothing like taking a trip through time and enjoying some childhood classics.
Most of my consoles still work. That includes - among the older ones, anyway - an NES, an SNES, an N64, two GBAs, a handful of DS's (I've amalgamated collections since getting married), a PS1, two PS2s, a PSP, and a few Segas that I picked up at a yard sale. Can't remember which Sega systems they were, but I know they work.
I'm pretty sure I have a non-functional Gameboy Color sitting around somewhere and the N64 and NES were getting a bit spotty the last time I checked, but other than that everything's working well enough.
I still have (in working condition!!) my original 1994 Sega Genesis. I have the original Sonic the Hedgehog, Sonic the Hedgehog 2, Sonic & Knuckles, Toejam & Earl, Taz... All of my original games still work.
I have my original working Sega Dreamcast with Sonic. (I am a huge Sonic fan ha). I have some fishing game too but those were really the only good titles that I remember.
I have my original working Playstation 2 with all kinds of games from Spyro to more recent titles.
I have my original working Xbox with the classic Halo series.
I have my original Xbox 360 (but it has some issues) - Halo
I have a PS3 (my 2nd or 3rd one, a lot of these died for some reason) - COD series!!!!
I have my Wii (my 2nd one, first one died) - Super Smash Bros Brawl!!!!!
My old Nintendo system (NES) should work if I plugged it in a good socket. I used to also own a Playstation 1 but it does not work anymore. Besides, most of the fun games for me were from the NES anyway. I got a lot of memories playing that thing. Sometimes, stayed overnight to finish a game. Contra, Rockman, Power Blazer, Warwolf,Airwolf and Green Beret were the titles I still remember.
I still have my Nintendo Entertainment System/ NES and Nintendo 64 up and still running. I also playing with it from time to time, although I am having a hard time find game cartridge for this console because they are really really old but still on a good condition.
I still have my PSP with me. I used to own a PS and PS2 but I can't find them anymore. Probably thrown away by my parents. It's kind of amazing and sad at the same time that my smartphone can emulate the PS and PS2 games perfectly. I have a handheld console in my pocket.