one size fuzzi bunz (6 pack for 114.00) they come with an insert and a doubler. they fit my 2 year old perfectly, they are soft , comfy,cute. he has plenty of room to grow in them.
baby kangas (6 pack 104.00) same as the fuzzi bunz) with a child that age you don't need too many. 12-18 would be plenty. pockets are awesome for that age. prestuffed they are quick to put on, and snaps. hold up better than aplix plus it's a little harder for kids to get off they don't seem as tempted as with velcro. hth
\ETA: i used AIO's fpr a long time and hated them. i will never buy em again. they just don't seem to get really really clean. i think it is all the layers and then the dumb "sewn in doubler" flap that gets bunched up and poop gets all under it, and the pul being attatched doesn't allow water to run through to clean (as it is made to keep liquid from going through).