Bike, Trike, Skuut for 21 month old?

[Marbie]

Long story short: We are getting my 4 year old DS a bike for Christmas (probably). If we do that, we need to get something that my 20 month-old DD can putter around on as well, so that she doesn't feel left out. She'll be about 21 months at Christmas.

So I'm wondering, what bikes, scoot-thingies, big-wheels, trikes, etc. have you had for your nearly-2 and 2 year-olds that you have liked? What have they really been able to use? I'm worried that a Skuut-type thing will be too hard, but they really are cute and look like good bike-prep.

Thanks!