This is obviously a debatable topic, but the GENERALLYaccepted tier system is found here:
http://super-smash-bros.wikia.com/wiki/Tier_list
In short, Mario is ranked 31st out of 38 characters and Meta-Knight is widely considered the best character in the game. This is of course dependent on the skill of the player(s). The tier system assumes 2 players of equal skill, etc.
Dr mario is not an unlockable character in brawl.
Baby Mario is a Trophy in Super Smash Bros. Brawl, but he is not a playable character. However, Yoshi, Mario, Luigi, Peach and Bowser are all playable characters.
no but it will be in Mario kart wii
super Mario galaxy and super smash bros brawl are the best
Baby Mario is a trophy, not a character. You can't use him.
super smash bros brawl by far!
No, Pichu is not a playable character in Super Smash Bros Brawl
Luigi. Mario takes all the fame.
The rarest character in Super Smash Bros. Brawl is Mario the plumber. You can only unlock him by completing 1,000 Brawls and finishing the Subspace Emissary.
Shadow is not a character in Super Smash Bros Brawl, unfortunately.
Midna is not a playable character in Super Smash Bros Brawl
What character?