I would love for my boys to love soccer the way DH and I do. If I could pick for DD I'd like for her to continue with gymnastics. DH would probably say he wants all of them to do triathlons too... Really as long as they all do something I'll be happy.
My kids have tried a lot of different sports. Lucas loves baseball. Tori loves dance.
However, for me to choose for them? Easy. Swim. I make them swim as their PE for school. During the year Tori swims laps with a home school training group and Lucas takes lessons in the same pool at the same time (works nicely!). In summers, our city has a big swim league involving all the neighborhood pools. So they do meets and stuff. All the other sports and stuff are by their choice but swimming is a school requirement because I feel it's first of all important to know how and second, swim is a sport you don't outgrow. You are never too old (until you are really really old!) to go for a swim. So I want to give them a lifetime fitness option.
I am not much of a hobby person myself, mostly just read a lot, and would love for the kids to have my love of reading. We are going to start DS with an instrument this year, he loves music, but has been a bit flipfloppy on which instrument he wants, he is torn between the piano and the guitar. The guitar would be cheaper for us to teach him because DH and my dad play and would be able to teach him, but he is always really into the piano when we go to Guitar Center.
We aren't really sports people, I played softball a couple years in high school on a community team but it was more for fun than anything. DS hasn't really expressed an interest in joining any sports, though I think we will be putting him into Karate for PE this year.