There are a lot of good games out there, but If I had to pick a certain amount, say... 10? I would choose these games.

Snes:

Super Mario World

Super Metroid

UniRacers

Mario Paint

Chrono Trigger

Earthbound

Mechwarrior 3050

Super Mario Kart

Super Street Fighter II Turbo

and Donkey Kong Country

3DO

Road Rash

Corpse Killer

Who the hell am I kidding? There are barely any good games for the 3DO...

Genesis:

Sonic and Knuckles

Boogerman: A Pick and Flick Adventure

Sonic 3D Blast

Earthworm Jim

Sonic The Hedgehog 2

Sonic Spinball

Gunstar Heros

Ecco the Dolphin

Bubsy in: Clawed incounters of the Third Kind

and Marble Madness

Wii

Donkey Kong Country Returns

Klonoa: Door to Phantomile

New Super Mario Bros. Wii

Wii Fit Plus

Wii Sports Resort

SqueeBalls

Super Smash Bros. Brawl

No More Heros

Animal Crossing: City Folks

not much else....

That is all for now. Will come back later... What about you?    

10 per system? That's a lot of games to try and find/list. If you're going to separate out by system, I think you're better off going with 3 each. It at least makes the list less daunting to read. So, mine are:

PS2:
Persona 3: FES
Nocturne
Shadow Hearts
Metal Gear Solid 2+3

PS3:
Demon's Souls
Metal Gear Solid 4
Killzone 2

360:
Bayonetta
Deadly Premonition

@Burzmali:
I should of put in on the blog, but I guess it really didn't matter how many were on there. For me it was 10 because I have WAY more favorites then 3.

That said...

Intellivision:

Kool Aid Man

Snafu

and Lock 'N' Chase. There is threee there because I don't have as many favorites for that system.

NES:
Castlevania 3: Dracula's Curse
River City Ransom
Super Mario Bros 3

SNES:
Legend of Zelda: A Link To The Past
Super Metroid
Super Castlevania IV

N64:
Conker's Bad Fur Day
Resident Evil 2
WWF No Mercy

PSX:
Metal Gear Solid
Final Fantasy Tactics
Castlevania: Symphony of the Night

PS2:
Shadow of the Colossus
Persona 3: FES
Persona 4
Metal Gear Solid 3

Xbox:
Ninja Gaiden
Shenmue II

Xbox 360:
Bioshock
Elder Scrolls IV
Dead Rising

PS3:
Uncharted 2
Demon's Souls
LittleBigPlanet 2

I could probably name off like 1000 more systems, but this list would be massive

PS2: