I like to play a game and trade it in,once I get tired of it. Most of the time,I don't even beat the game. I traded in resident evil 6,mass effect 3 and call of duty for crysis 3. I did'nt play through the ada campaign,but played the rest and barley played mass effect 3 at all. So the only games I own right now are crysis 3,assassin's creed 3 and far cry 3 on the ps3. lol     

Too many to list, I sell my games very rarely.

I don't sell my games. I'm too attached to them :)

I used to sell games, but no more, so I currently own approximately=

34 PS2 games (I have owned more like 70)
25+ 360
100+ PS3
20+ PSP
8+ Vita

Steam says I have 98 games, I have a few Origin games too

Also, 15-20 PSN games

So I own loads!!!!!!!

I never sell my games. I probably have nearly a thousand if Steam (and other digital) is included. I even have multiple copies of certain titles that are out of print, probably worth some money.

I don't sell my games, so, currently, I have, boxed:

9 N64 games
20 PC games
6 360 games
1 Wii game
1 PS2 game
3 DS games
7 3DS games

I almost never sell my games, so the list would be too long, since the Mega Drive.

Why so few games across so many systems?

I almost never sell my games and even if I wanted to, german stores usually reject UK imports, which is where I get about 80% of my games. I also buy a lot of games digitally.

Retail games I have:

10 Wii U games
5 PS3 games (right now it's 4 but I just ordered Dishonored PS3 for 15€ incl. steelbook)
8 DS games
13 3DS games
11 Wii games
6 PSV games

29 PS3 games

2 Xbox 360 games 

16 DS games 

6 PSP games 

8 3DS games 

7 PSV games 

3 Wii U games