That is a very hard question, Because everyone likes to use different pokemons.
My own team (Which i really enjoy playing with) is:
Charizard
Alakazam
Aerodactyl
Gengar
Gyarados (Or Dragonair)
Raichu (Or other Electric Pokemon)
It's a Smart Strategy to try using different Types of Pokemons, So you won't have Six Pokemons that are all Fire Type^^
Good Luck!
On top of mt ember.
The top of Lavender Town's tower
save mr.fuji from Pokemon tower top floor and get the poke flute
If you mean Pokemon FireRed/LeafGreen on the GBA, the mansion is in the top left corner of Cinnabar Island. (home of the seventh gym)
The Pokemon Mansion is at the top of Cinnabar Island near the Gym. There you can catch any fire types like Vulpix. You can also find Muk and Grimer.
At the top of Pokemon tower.
top of Pokemon tower
The Pokemon Mansion is in the top right corner of Cinnabar.
On top of mt ember.
Moltres is at the top of Mt. Ember.
Two off the top of my head are: Wobuffet and Heracross.
Moltres can be found on top of Mt Ember.
in a pokeball on the top floor of celadon mansion.
Moltres is at the top of Mt. Ember.
The top of Lavender Town's tower
Go to the top of mt ember.
You battle all of the trainers inside the building. Try to get to the top.