Professor Oak
He's the leading dude when it comes to pokemon, and there's practically nothing he doesn't know! Set up in Pallet Town, his lab is a place where he can let trainer's pokemon run about, and study them at the same time. He has started many young trainers on their path to becoming pokemon masters, and was the one to give Ash his Pikachu. Gary is his grandson, and although I have no idea what Gary's parents are (or were) like, his grandfather sure is the opposite of him. Professor Oak is a great friend of Ash's parents, and he spends a lot of time checking up on Mrs. Ketchum, to see how she's doing. Ash and friends meet up with Prof. Oak often, and just recently he has gotten his own radio talk show with DJ Mary in Goldenrod City. Although we don't get to hear much about Prof. Oak when he was a trainer, we do get to see him as young Sammy in a certain pokemon movie...