Donkey Kong is my #1 pick when he is available, that's who I always select now when playing Mario Party Superstars. He's always been my favourite and there usually isn't any fight over who gets to pick him when playing with others lol.
Growing up the Mario Party game I owned and played the most was Mario Party 7 where Donkey Kong isn't playable so back then I would mostly play as Toadette.
I've only played two Mario Party games, so in Super Mario Party, definitely Monty Mole! In Mario Party Superstars, I've only played as Birdo. My back-up in both instances would probably be Daisy.
I'd always pick Yoshi in the older games, and pick Boo in the later games. I was obsessed with both growing up. They are my favorite Mario characters to this day.
When we played one of the older Mario party games, I always picked peach. (Still do, really). But back then it was specifically for spamming the "i am the princess" taunt. Drove my family up a wall, and i like to think it gave me a real psychological advantage. If you just save your coins and don't steal my hotel, I'll stop taunting for a while.
I’ve always chosen Yoshi as my main in all the older Mario Party games I’ve played and for Mario Party Superstars, sometimes I might choose Peach if Yoshi was taken by someone else. Super Mario Party I like to alternate between Yoshi, Bowser Jr, and Pom Pom.
Depends on which characters are on the list. Sometimes Luigi or Donkey Kong and I think in the newer ones Drybones and Shyguy are in it, but I could be wrong. So I picked one of them. I haven't played in ages though, so I could be remembering things wrong.