I plan pretty much every single Pokemon I'm going to catch and before I even buy the game, if I can. When I was younger, I'd just play with what Pokemon I saw on the anime and liked the design of and with absolutely no form of strategy. Nowadays, I'm meticulous in my team planning, with thought given to final typings, movesets and levels that I want my team to be at pretty much all stages of the game. While some people might say it takes the fun out of the game, to me the fun comes from all of this planning!
Yes, I'm well aware of how weird that sounds, but just go with me! :P