I recently broke out the old Wario Land 4 GBA cart to play through before Wario Land Shake hits NA. I had forgotten how great of a game it was. It's the only Wario Land game I've played through (I actually scored a Wario Land 2 GB cart this evening for $4, I'll be getting the first one for the GB, and 3rd for the GBC as well tomorrow. 

I used to (and still do) love 2D platforming games, and wondered if I've missed any great titles over the years.

A few of my all time favorites.....

Super Mario Bros. NES Nintendo 1985
Mega Man NES Capcom 1987
Prince of Persia Broderbund 1989
Mega Man 2 NES Capcom 1989
Ninja Gaiden 2: The Dark Sword of Chaos NES Tecmo 1990
Super Mario Bros. 3 NES Nintendo 1990
Mega Man 3 NES Capcom 1990
Super Mario World SNES Nintendo 1991
Sonic 2 Genesis Sega 1992
Contra 3 SNES Konami 1992
Super Metroid SNES Nintendo 1993
Super Mario World 2: Yoshi's Island SNES Nintendo 1995
Castlevania: Symphony of the Night PSX Konami 1997
Wario Land 4 GBA Nintendo 2001
Contra 4 DS Konami 2008

What are your favorites? Please list what console they were/are for, and if you know it the year released.

If you haven't already, you should definitely play Castlevania: Aria of Sorrow (GBA, 2003). Harmony of Dissonance and Dawn of Sorrow are very good as well.

Also, Ninja Five-0 is a fantastic, painfully overlooked GBA title from 2003.

Contra
Super Mario Bros. 3

Metroid

Honorable Mention: Bubble Bobble, Teenage Mutant Ninja Turtles (this game taught me the importance of bieng able to have saved games!)

I see that Ninja Five-0 is actually in your collection. Well played.

Well, I've only played 3.

Super Mario Bros. 3 (The Remake on GBA)
Super Mario World (The Remake on GBA)
New Super Mario Bros.

Ninja Five-0 is a GREAT game. i thought of a few more..

Mappy Arcade Namco/Bally/Midway 1983
Kid Icarus NES Nintendo 1987
Donkey Kong Country SNES Rare 1994
Ninja Five-O (Ninja Cop in EU) GBA Konami 2003

Mappy is way old school now, but I can't tell you how many quarters I fed that machine in arcades.

Oh yeah, NSMB, how could I leave that out....

No Metroid: Zero Mission or Mischief Makers (N64)?

Super Mario games
Megaman 2 & 3
Metroid, Super Metroid
Simon's Quest: Castlevania II, Super Castlevania
Ninja Gaiden 1 (NES and TG16)
Strider (NES, I didn't play the Genesis one 'til much later)
Sonic 1,2
Contra Games

I can't believe I forgot, Duck Tales (a woo-oo) and Aladin (I liked both versions, leaning Genesis)

Oh! There were also the 2D levels in SMG!