23.
NES - Bought at an old antique shop. Still works, amazingly enough.
SNES - Bought the same day as...
Nintendo 64 - Bought at the same little antique shop as the NES. We had found out they recently got some more gaming systems, so we went over and bought said gaming systems. xD
Playstation 2 - Bought JUST before they discontinued them, so I've had to get most of my games for it off eBay. ):
Game Boy Advance - My neighbor ran over one, thought she ran over a chicken, found out it was a GBA, and gave it to me.
Game Boy Advance SP x 2 - This was the first gaming system I ever owned. Got it for my birthday from my neighbors, since I kept stealing theirs anyway. Then my parents bought me another one since I wanted to trade Pokemon with myself.
Gamecube - First console I ever owned. A beautiful limited edition Pokemon XD: Gale of Darkness version~ <3 Still own it to this day, in perfect working order.
Xbox - It was my Dad's but I played it more than he did. Lego Star Wars! x3
Xbox 360 - Me and my Dad share ownership of it. He plays it more, though.
Playstation 3 - Just got it this Christmas, I play it the most out of all of my consoles. It has so many good RPGs...
DS x 1, DS (Lite) x 7, DSi x 1 - Don't ask. Let's just say that DS Lites are poorly made.
PSP - Got it for my last birthday along with Tales of VS and Tales of the World: Radiant Mythology 1. Needless to say, I didn't use it much.
Wii x3 - My Mom insisted on owning one for each TV. And this woman wonders why we're in debt... >_>
...Yeah, don't ask me to list my games. xD