Good question. I still have never ever traded in a game, not sure why. Maybe its because I think I might want to play them later.

Definitly the PS3 which I probably bought (including digital) something stupid like 200-300 games.

However thats a miss leading answer as when the PS1 was around (which would probably be a close second, though most were bootleg) and the PS2 was around my financial situation was no where near as healthy, in fact during the PS2 and first couple of years of PS3 I was paying to an IVA due to insurmountable debts. But I completed that 3 years ago which meant I could afford to buy as many games as I wanted.

Going back to pre-PS1 I was at school and couldnt even afford to buy my own console.

If my financial position remains as it for the next 8 years or so I can easily imagine my PS4 taking over the PS3. Its already at 20+ games.

So far on this Gen i've bought the most games for PS4. So far I have 9 games and there are a lot more I want.

PS1. Lost count.

I have around 60 wii games, some ill admit arent spectacular but they had their charm or niche that the PS360 lineup didnt satsfy. Plenty of underated and overlooked games on the wii. 

Atari 2600 1 CIB 15 loose
Atari 5200 1 Loose
NES 15 CIB 141 loose
SNES 4 CIB 38 Loose
N64 23 Loose
NGC 25 CIB 3 Loose
Wii 41 CIB
WiiU 31 CIB
GB 10 loose
GBC 1 CIB 4 loose
GBA 1 CIB 6 loose
DS 6 CIB 3 loose
3DS 10 CIB
SMS 3 CIB 4 Loose
Genesis 54 CIB 29 Loose
32X 2 CIB
Sega CD 22 CIB 2 Loose
Saturn 39 CIB 8 Loose
DC 50 CIB 1 loose
Game Gear 1 CIB 4 Loose
Xbox 102 CIB 1 Loose
X360 53 CIB
PS1 1 Longbox 21 CIB 12 loose
PS2 61 CIB 1 loose
PS3 31 CIB 1 Loose
PS4 2 CIB

Not counting PC, because over the decades that one would naturally easily win, the console I got the most games for is the N64 at almost 50 games. Not really sure, because they're in another house (no I'm not rich, most of my games for N64 are at my father's house), but from the top of my head I have 47 of them.

After N64 comes PS3, with about 40 games. The N64 is indeed my favorite console, but PS3 is not my second favorite. That honor goes to PS1. PC is seperate here to, because while many of my all-time favortie games are in fact PC games, the system doesn't really have it's own 'identity'. I can't exactly relate to the PC as a system like I can to any console and thus can't talk about in the same way.

I had a tonne of games for my PS1 and PS2. Probably around 50 each. I didn't really buy them though, my dad used to either pirate them or buy them in bulk.

If I'd include pirated games I used to have about 200 DreamCast games and it would win, even from my pirated PS1 collection . In reality I only have a little under 20 legal copies.

Definitely 360.