Ah, Pokemon G/S/C. Fond memories of goign around Jouto getting all eight badges with my Chikorita.
GSC was the best generation- just the right amount of Pokemon (what is it now? 486?), new stuff like breeding/genders, and the PokeGear (which could help you get a Master Ball!).
The only thing I absolutely hate about the game (besides the battle system) is the amount of effort it takes to catch my favorite Pokemon:
This is Clefairy. Innit cute? Hard to catch, but worth it just to say "Yeah, I caught the lil' pink marshmallow dude!"