Over the entire lifespan of the console, easily over 50. Most of them i wait for a drop in price though.

I've at least tested them all out, but there are a lot that I haven't really put any significant time into yet.

I don't know how to answer this question...

It's 50+ for my PlayStation systems..

My Nintendo handhelds tend to hover in that 20-30 category, my Nintendo consoles are usually 8-12, and my Xbox ones are usually 4-7.

I'll likely end my Wii U collection around 50 games, maybe 60 if we include digital. For my 3DS, it'll probably be around the same.

I find that 50 is just the magical number for me; it's what I used for the PS3. My PS2 probably had around 40 games. So yeah, just in the range of 40-60, and then I'm generally ready to move on.

So far I've had:
SNES: 10
N64: 7
PlayStation: 2
GC: 35
PS2: 5
Wii: 30
Wii U: 5

Game Boy (including Colour games): ~20
GBA: 15
DS: 40
3DS: 50

Console-wise, GC and Wii were heaven. So many incredible games between them. As much as I love The Wonderful 101 and Pikmin 3, Wii U has.. not been great on that front. I always buy more handheld games as I spend more time with my handhelds and the last two gens have been great for that. I was 15 when the 3DS debuted and it was the first console I bought by myself, so I've had lots more money to spend on games for it (and the DS in its later years.)