Pokemon Sapphire. Ay caramba, Steven was harder than I remember. He was able to counter my two secret weapons Torkoal and Hariyama flawlessly (earthquake and psychic).
>>Nightwatcher
You mean Shippou City Gym?
I know, that is a tough one.
A lot of training would help, and having a fighting Pokémon on hand may help a lot too.
For the book shelves, look at this:
http://www.youtube.com/watch?v=D3jqC1-q2y4
(Click "Shippou Gym" to go there directly.)
The first one has better stats (except for speed) and has levitate, protecting it from Ground attacks. But according to Bulbapedia, its first form is rare.
The second one is part bug and can learn bug-type moves which could help me out against one of the Elite 4 members.