I like fighters which I can fundamentally understand through all the practice I am willing to put in. If the character has moderately easy combos to pull off, above average, but not too fast movement, a projectile to get the opponent off guard, and above average damage output, I would like to play as that character.
Smash Melee: Sheik, Marth
Smash Brawl: Lucas, Olimar, Pit
Smash 4: Pit
Joy Mech Fight: Giant, Sukapon
BBTAG: Noel Vermillion & Chie
Pokken: Chandelure (but I like most characters and the game loop)