While I originally went with LeafGreen, I suddenly remembered that I also have SoulSilver. Now I want to try it with SoulSilver... problem is that I have no way to transfer my event Pokemon (Nintendo USB wifi connector does not work on Vista/Win7, no one with a similar or later game around, WPA connection so can't transfer online), and so I'm hesitant about erasing my first file.
I would just go with LeafGreen but SoulSilver has a wider variety for me, so I'm not sure what to do here. :( Not to mention LeafGreen is much more predictable (I've played through it at least 3 times) and I've only ever gotten halfway with SoulSilver (beat Gold once) so SoulSilver would definitely be a lot more fun to try a Nuzlocke on.
EDIT: Welp, it's been done. Old file is gone. :I