I was actually, and this will sound CRAZY, considering...making the Hall of Fame...with every Pokemon. I would probably do generations I-IV on HeartGold though, because I really, really hate migrating/transferring to the next gen. idk why. But I'm not even done with the Gen V version of this, so WHY am I considering the others? I don't even know.
And I worked it out, I would divide it by generations. So in gen I, I would use Scyther, Electabuzz, etc because in gen I, they didn't evolve. But in gen IV (and well, any other gen with a baby Pokemon) I would use the baby Pokemon, provided that it's evolution isn't also in that generation. Basically, I would be treating it as if it didn't evolve. (example would be using Chimecho in gen III, since it had no baby yet, but when I move on to gen IV, I would use Chingling, since it was introduced in gen IV. Riolu is also a baby, but it's evolution, Lucario, was introduced in gen IV, so I would go with Lucario, not Riolu.) This doesn't even make sense to anyone, I'm sure. :(