Do you have any Pokemon that was your favorite, but thanks to the introduction of a new Pokemon in a next generation, your favorite 'mon were replaced by other? What were these Pokemons?
For example, I used to consider Yanma my favorite Pokemon of all in Gen 1 and 2, but when Gen III was launched out, it was replaced by Milotic as soon as I used it.
Then, Milotic was my favorite Pokemon until Gen IV, when it was replaced by Lucario. Lucario got my attention mostly because of SSBB.
Unfortunatelly, in Gen V, Lucario were replaced by Volcarona. That fire bug is a killer when using special moves, I loved it!
Volcarona is now my favorite Pokemon of all and it will keep as my favorite if Gen VI doesn't introduce one that make me like more than it.