The Silver Gold Chrystal series. I liked being able to go back to Kanto after wards

Has to be Crystal and Gold,I never get tired of playing them!^^

Gameboy:Red Sorry I just had and still have a hard time getting into those games and now I am terrified of playing them I am only saying Red because thats my favorite color
Gameboy Colour:Silver.I can't remember what they are like as my Silver does not save!Stupid game
Gameboy Advance:Ruby/Sapphire/Emerald.Strange thing is I get a nogalistic feel only from these three games.
DS:All of them so far but my least favorites are HeartGold and SoulSilver but I do still like them but I couldn't get a nogalistic feel from them but hey they are great!