Back when I was in first grade, Pokémon was the coolest thing ever. Most of my classmates talked about it, but I still didn't get Platinum, my first game, until fourth grade. (I kinda missed that bus :/) Even so, I was FASCINATED by these creatures that could change and battle. Even so, I was pretty bad at it, and I beat the Elite Four with a team made up of half other people's 'mons. Soon enough, I got SoulSilver, where I got my first Lv100 Pokémon, the Typhlosion I had from the beginning. Eventually, I got White, then Black 2, and finally Y, which I beat within a week! Lately, I've been creating my own region called Jivon and the Pokémon inside of it.
Bug
I'd say Crustle. With its high Defense and Attack stats and a diverse enough move pool to cover all three of its weaknesses, this guy would be a must-have for a Bug-type team.
Dark
Bisharp. Just plain Bisharp. Just 'cause it has a 4x weakness doesn't mean it can't be AWESOME. This guy is both of my favorite types, and learns Night Slash, one of my favorite moves to date. Plus, just look at it.
Dragon
Tough choice, but Tyrantrum. The Strong Jaw Ability, already high Attack, claimed to be unconquerable, Draco Meteor, the list goes on and on.
Electric
Magneton is the coolest here. I've always been interested in magnetism and electricity, so this Pokémon was right up my alley. It has high Special Attack, making Magneton a good Thunderdacer if you need one.