Mine is undoubtedly Emerald. It's a game with so many features: phone, more secret den components, Rayquaza before the Poke League, both Groudon and Kyogre at Level 70, the Battle Frontier and the epic story with Groudon & Kyogre's battle!
Unfortunately, I cannot replay it as my friend who I lent it to happened to lose it! Un-fricking-believable!
If we were to go by gen/region I would say Jhoto. I've play and beat Gold, Silver,Crystal, and Souls Silver. The only reason I've voted for Soul Silver is because of the things they added to the game. Also Emerald and White are tied in second. But I'm leaning towards White because Liligant is kickass!
I picked Soul Silver because it is simply awesome and has everything the other games had but better (except for the Game Corner, which was the biggest disappointment of the game)
My favorite would have to be Pokemon gold because it is the first I have ever played and liked it ever sense. If I would of never found it while helping my friend moving some boxes around (And yes I did ask if I could have it, I did not steal it.) I probably would have never got into Pokemon like today.
I chose Pokemon Emerald because it was my first game in the series and I always found myself going back to replay it.I'd say that Platinum is my second favorite with the addition to the Twisted Dimension.
Fire Red. Thats when i got my first Charizard. And it was the first one I ever played. I played he heck out of it. I didn't even get a new one untill i cheated my cousin out of soul silver
Well it definitely has to be both hg/ss and g/s. As a kid I gave so much time and effort to that game and when the remakes came out I was too overjoyed for words. They did an outstanding job with those games and that really set the standard for what a good pokemon game should be. I originally played it on the old fat gameboy until I got a gameboy color that Christmas. Good memories with that game.