Gen 1- 2nd and 3rd placer is always switching between Tauros, final stage starters, Lapras, Electabuzz and Gengar but Scyther remains top 1.
Gen 2- Back then: Typhlosion/Donphan
Now: just Donphan, I'm underwhelmed by the current always fireless default model.
Gen 3- Back then: OG fire fighting chicken.
Now: deoxys. It's a cool concept now overused.
Gen 4- pre-diamond and pearl official announcement: weavile and buizel
Back then: dialga
Now: buizel is so fucking cute and now I'm an adult who doesn't care for what the might say.
Gen 5- Meh overall but great kaiju inspired designs as well so Haxorus, Hydreigon, Terracosta, Volcarona or Pawniard could've worked just fine.
Gen 6: I hate everything it represents and I'd like to erase it from the series but Tyrantrum and shiny Crawlitzer are redeemable. If only mega lucario were just an evolution...
Gen 7- It's a purple alien-dragon-wasp.