VGFacts

Might as well update this while it's up here:

PlayStation
PlayStation 2 (Original and Slim)
PlayStation 3 (Original and Slim)
PlayStation 4
PSP
Genesis (Oringanl and model 3)
RetroDuo (NES/SNES)
NES
SNES
Nintendo 64
(Broken) GameCube
Wii
(Broken) Game Boy Pocket
(Broken) Game Boy Color
Game Boy Advance (Original and SP)
(Broken) Nintendo DS
Nintendo 3DS XL
Xbox
Xbox 360

I might as well do the same. Update:

Switch
NES
SNES
N64 (wife found it for free!)
Gamecube (wife found it for free!)
Wii (black, does not play GC games)
3DS XL Gold Edition
2DS (my younger daughter's but it stays at my house) 
Donkey Kong II (Game & Watch) 
Xbox
Xbox 360

OK then, my collection:

Atari 2600
NES
SNES
N64
GameCube
Wii U (8GB Launch system)
Switch (Launch system)
Game Boy (only system I've never got rid of. I've had it since I was a kid)
Game Boy Color
Game Boy Advance
DS Lite
3DS (Launch version)
Sega Genesis
Playstation
Playstation 3
Playstation 4

for a grand total of 16 systems.