Raichu

I would like to speak in defense of my favorite Pokemon, Raichu.

I prefer Raichu over Pikachu, and I hate to think that people would scorn it because they like Pikachu. Raichu's superior stats are an obvious plus, and in my opinion it looks much cooler. I believe that many underpowered lineups could be improved with some evolution, if the trainer was only willing. 
I think Raichu gets his bad reputation due to Pikachu's popularity. Pikachu is the most popular Pokemon in the original games, therefore not many members really wished to abandon him. So, Raichu, for the most part, was ignored by most trainers, despite him being a highly effective Lightning type Pokemon due to his pre-evolved form's popularity.