NES

Super Mario Bros./Duck Hunt
The Legend of Zelda
Tetris
Marble Madness
Top Gun: the Second Mission
Gun.Smoke
Super Mario Bros. 2
Super Mario Bros. 3
Teenage Mutant Ninja Turtles
Al Unser Jr. Turbo Racing
Ice Hockey (briefly)
Ernie's Magic Shapes/Astro Grover

VIRTUAL CONSOLE

Donkey Kong
Mario Bros.
Lost Levels

GAMEBOY ADVANCE

Super Mario Bros.
Super Mario Bros. 2
Super Mario Bros. 3
The Legend of Zelda
Zelda II
Dr. Mario
Donkey Kong
Mario Bros.

GAMECUBE

Zelda II
The Legend of Zelda
Mega Man
Mega Man 2
Mega Man 3
Mega Man 4
Mega Man 5
Mega Man 6

for vc because the only game i have for nes for the vc is super mario bros. 3

For VC I have Mario Bros., Donkey Kong, and Lost Levels.

Okay, lets see:

Super Mario Bros. - Tetris - Nintendo World Cup 3in1 cartridge
Super Mario Bros. 2
Super Mario Bros. 3
Mega Man 5
Kirby´s Adventure
The Lion King (bad !)
Tennis
Donkey Kong Classics
Pinball (I bought some of these damn boring "Classics" because they were much more effortable)
Days of Thunder
Star Tropics (747 !!!1)
Yoshi´s Cookies
Dr. Mario
Battletoads (my mom it away from us later, dont ask why...)
Duck Tales 2

Later I could lend some games for a longer time:
Mega Man
Mega Man 3
Excite Truck
Tiny Toon Adventures

As you can see, one of the most "missed" games were Metroid and The Legend of Zelda. Thanks to the VC, I could close that gap. After getting well with Metroid I even did a amateur speedrun and 100% run.

I forgot Ernie's Magic Shapes/Astro Grover. I probably sold it.

This is a list of the games I currently own.
Anticipation
Balloon Fight
Bionic Commando
Castlevania
Clu Clu Land
Cobra Triangle
Devil World
Dr. Mario
Duck Hunt
F-15 Strike Eagle
Ghost'N Goblins
Golf
Gradius
High Speed
Ice Climber
Kung Fu*
Mega Man
Mega Man 2
Metal Gear
Pinball
Puzznic
RoboWarrior
Rush'N Attack
Section Z
Solomon's Key 2
Solstice: The Quest For The Staff of Demnos
Spy vs Spy
Super Mario Bros
Super Mario Bros 2
Super Mario Bros 3
Teenage Mutant Hero Turtles
Tetris
The Goonies II
The Legend of Zelda
Track and Field II
Track and Field In Barcelona
Trojan
Yoshi's Cookie
Zelda II The Adventure of Link NES

My memory's hazy, but back when I had an NES, I know I owned these games:

Batman
SMB
Snoopy
A pinball game (not the one on the VC, but some different one whose name escapes me).
A top-down shooter similar to Xevious (it may have been Xevious, but I'm not sure.)

And on the VC I bought SMB3.

I owned Golf.
I took it when my friend moved and gave much of his old stuff away. I don't and didn't have a NES though

Currently i only have maybe a dozen or two carts, including the Zeldas, Marios, Metroid, Kid Icarus (2 for some reason?), Solomon's Key, Bases Loaded, DK Classics and some others. But back in the day ... oy, probably 50-100 carts easy. Some got traded in to FuncoLand as college required more $ and time for drinking and women, and a bunch more bounced around amongst my friends. I actually discovered just a couple years ago that one of my friends had most of my old carts packed away with his NES, which he and his young son were now enjoying together (so obviously i didn't reclaim them).

Titles I used to own:
Ninja Turtles
720

Titles I own now:
Super Mario Bros.
Super Mario Bros. 3
Mike Tyson's Punch-Out!!
Punch-Out!! featuring Mr. Dream.
Tetris
Star Tropics
Kirby's Adventure
Fung Fu
Ice Climbers
Metroid
Super Glove Ball
Ninja Gaiden 1-3
Baloon Fight
Bubble Bobble
Wrecking Crew
Kid Icarus
Dr. Mario
Master Blaster
Kid Niki
world Class Track Meet
Super Mario Bros./Duck Hunt
Gumshoe
and a few that I would have to go see that I have...

On VC:
Kid Icarus
Teenage Mutant Ninja Turtles
Galaga

The only games I don´t own anymore are Popeye and Chip ´n Dale. I chipped them in for Legend of Zelda and never regreted it.

The NES games I used to own are long gone. Lost, stolen, traded, or sold. In no particular order:
SMB
Duck Hunt
Hogan's Alley
Gyromite
Kung Fu
Metal Gear
Metroid
Commando
Legend of Zelda
LoZ II
Contra
Ultima: Quest of the Avatar
Deadly Towers
Pro Wrestling
Rygar
...Those are the games I remember owning outright. Everything else I played were rentals or loaners. And I never had all of them together at once. One time I came home from school and all of my NES games at the time (probably just 3 or 4) except Super Mario were gone. My mom told me she had given them to a friend so her son could play them............. on his Atari.

I forgot that I've twice owned Zelda II. I got it with the Zelda collection and later for the GBA. Big mistake.

@Bikeage: You're mom obviously had little to no clue what a "video game" was. LOL