Charmander > Charmeleon > Charizard.
Fire to Fire/Flying. 3 weaknesses and 5 resistances to 3 weakness, 5 resistances and 1 immunity. i like...
Decent Speed and Sp. Atk and well-rounded other stats...but if fast enough and powerful enough, its kinda low defense won't be such a problem.
Cyndaquil > Quilava > Typhlosion.
Fire. 3 weaknesses and 5 resistances. cool...
Pretty much the same stats as Charizard...
Torchic > Combusken > Blaziken.
Fire to Fire/Fighting. 3 weaknesses and 5 resistances to 4 weakness, 6 resistances. ok...
Superior Attack and Sp. Atk. Horrible Defense, and average speed. Needs 2 be faster...
Chimchar > Monferno > Infernape.
Fire to Fire/Fighting. 3 weaknesses and 5 resistances to 4 weakness, 6 resistances. ok...
Decent Attack, Sp. Atk, and Speed. Slightly better Defense and Sp. Def than Blaziken but lower HP. Great if it's fast and powerful enough to make defense less of an issue.
I go w/ Charmander. Charmander and Cyndaquil are like the same, but Charizard has the immunity to Ground and Typhlosion does not. Infernape comes in at 3rd because of its speed and attack, but low hp makes it hard when dealing w/ night shade, seismic toss, dragon rage, and sonicboom. Blaziken just sucks when it comes to everything but attack power.