I've had many an in-game team, but I'll go with my all-time favorites from them:
Took through Kanto in FireRed.
Took through Sinnoh in Platinum.
Took through Hoenn in Emerald Version.
Took through Unova in White Version.
Took through the Sevii Islands in FireRed Version.
EDIT: Come to think of it, some of my in-game Pokemon from FireRed and Emerald are in my sig. XD