Lessee here.
I have the NES-Wii, a PS1-PS3, an original brick sized Game Boy, a Game Boy Advance SP, Two DSs, and a Game Gear.
Game wise...
NES: Mega Man 2, Mega Man 4, G.I. Joe, Double Dragon II and III, Super Mario Bros/Duck Hunt, Super Mario Bros. 3, Strider, Ducktales, Ninja Gaiden 2, The Legend of Zelda, and Kirby's Adventure.
Super NES: Donkey Kong Country 1-3, Super Mario World, SMW2: Yoshi's Island (has anyone else played this game and enjoyed it?), Final Fantasy Mystic Quest, Mega Man X, Mega Man 7, Sunset Riders, Aladdin, Kirby Super Star, and more I can't remember.
Game Boy: Pokemon Red, Blue, Yellow, Gold, and Silver, Metroid II: Return of Samus, Super Mario Land 1, 2, and 3 (wario land), The Legend of Zelda: Link's Awakening, LoZ: Oracle of Ages/Seasons, Mega Man: Dr. Wily's Revenge, Mega Man 2, World Cup, and Super Mario Bros. Deluxe.
Nintendo 64: Goldeneye 007, The Legend of Zelda: Ocarina of Time and Majora's Mask, Super Mario 64, Donkey Kong 64, Quest 64, Pokemon Stadium, Star Wars: Rogue Squadron, Star Wars: Shadows of the Empire, Mega Man 64, Paper Mario, Star Fox 64, Banjo-Kazooie and Tooie, and Kirby 64.
Game Gear: Sonic 2, Sonic Triple Trouble, and some golf game my dad bought.
PS1: Final Fantasy VII, Final Fantasy Origins (I-II), Final Fantasy Chronicles (Chrono Trigger and IV), Final Fantasy Anthology (V-VI), Resident Evil 3, Mega Man X4, Mega Man X6, Mega Man 7 (as you can see I love all things Mega Man), Chrono Cross, and more I [see above]
PS1 is a section I'd really like to expand more. I HAVE FFIX and FFVIII, but both are not in working condition up to a point (Disc 3 on both, I think). I at least beat FFIX but never FFVIII. I'll get them off eBay at some point.
Really, there's multiple games that I'd like, like Mega Man X2 or Mega Man 4 and 5 for game boy. I'll get them off the internet or something.