Mine is Pokemon Emerald. a lot of people seem to hate Gen III but i enjoyed it much better then other people... i was really young when i played it on the VBA emulator, got to the Elite Four but couldn't beat the last... Pokemon Alpha Sapphire is my chance.

GlazedKitten : Mine was Pokémon Silver for the gameboy advance..It may have had old graphics but to me that was the first game I ever played..Seriously! My first game was a Pokémon Game and my First system was a gameboy advance and when I played it..I felt so attached to it..I took it everywhere I went and even put it under my bed as I slept..I love Pokémon and will never stop playing it..I beat Pokémon OmegaRuby in a total time of 35:55 which only took me three days..I even stayed up all night playing it..Yes I am a hardcore fan..I beat pretty much all of the Pokémon games except for Pokémon Snap..Which I can't get into..Everytime I hold my Gameboy Advance I remember the times I played Pokémon Silver..And the experience of playing a game for the first time..Haha! I still remember I had no idea what to do when I first played it..Even though its the easiest game to get into.

my first pokemon game was Sapphire. it was given to me along with a Gameboy Advance (not sp) for my birthday. i was so pulled into it that i had it with me everywhere i went and played it as much as possible. 
GlazedKitten : Not many people like Gen III? Nooooooooo. as far as i can see, almost everybody i know agrees that Gen III was the best. it has gone far enough to bring one of my friends, who is TOTALLY against a DS of any sort due to Gen VI and past, to figure it out to buy a 3DS just to play Alpha Sapphire, because like me, sapphire was his first and favorite. wait no, his first was fire red. but his favorite is Sapphire

My first Pokemon game was Pokemon Blue. I remember trying to decide on one Gameboy game to buy and it was either Mario Tennis or Pokemon Blue. It took me a while to get used to Pokemon Blue since I started when I was younger. If it wasn't for that decision that I made when I was younger, I would have never gotten into Pokemon at all.

My first Pokemon game was Pokémon Red. I started watching the anime series, episode 25 Primeape Goes Bananas, to be exact, and was instantly hooked. I was so excited about the game, even though it was on the Gameboy Pocket. I started off with my little Charmander and never looked back. Today I have at least played, or cleared the majority of the Pokemon games, including Green, and still waiting to try my hand with Alpha Sapphire and Omega Ruby.

my first pokemon i played is pokemon leafgreen
the first adventure was really hard for me
i played pokemon everyday i like pokemons and i have a toys, cards, and other like gba and on computer
next is pokemon sapphire i really tought i can't finished my adventure the adventures are hard for me
but then on the other side it's not i complete and defeated the champion

I believe that my first Pokémon game was Pokémon Crystal, however, the game that made me love Pokémon was Pokémon Mystery Dungeon. I just really liked that game and the story. I never finished that game but I'm planning on finishing that game.

GlazedKitten : I also loved gen III. I think it was the best gen ever! Though I love gen III my first pokemon game was Pokemon Red. It was the game that got me into RPGs.

My first Pokémon game was Pokémon Pearl. It was fun, but I didn't really get into it that much. I got far, I beat the game, but it got a tiny bit boring... I don't know anyone who thinks Gen 4 was their favorite . Gen 5 was so much more fun for me .

I think if I remember my childhood, the first Pokemon game I have every played was Pokemon Red on the Game Boy, and if I remember, it took me like months to go from starting the game to defeating the champion (now it's all done within 2-3 days). Ahhh, my childhood.

I think the first Pokemon game I ever played was actually Gold. However, I wouldn't have had much time with it, since it belonged to my little sister. I doubt I even made it past four gyms, much less gotten to the Elite four or beaten it.