My old save file in SoulSilver had the shiny legendary trio and Celebi from the download events. I traded them and my Totodile to HeartGold before deleting my save file and starting a new one. Like the other games in my Pokédex Quest, I am starting 3 times and trading my starter so that I can have data for all three from the beginning.
Silver is officially starting with Totodile since Gold started with Cyndaquil and I'm not a big fan of Chikorita. I'm going to soft reset for a nature that boosts Attack or Speed.
Edit: Well, I didn't keep a nature that boosts Attack or Speed. I kept a Rash Totodile (+Special Attack/- Special Defense) with Mischievous as his Characteristic. I couldn't pass up a Pokémon with a perfect Special Attack IV and a nature that boosts Special Attack.
After delivering the Mystery Egg to Professor Elm, I caught Hoothoot and Rattata on Route 29 and a Geodude on Route 46. I traded Rattata and Hoothoot to Gold for my Chikorita and Cyndaquil. I saved at Cherrygrove, ready to move on.
Current Pokédex Completion: Seen 6, Obtained 6.