Mr W ( 20 mos ) prefers kids 2-5 years older than he is.
Kids his age he tolerates. But he is not enthusiastic, either. When he is around kids his age and gets bored, he will grab some books and sit by himself. I think the latter behavior is a good one. We've gotten him to say hi to everyone - but he does not have to play with anyone.
If another kid tries to bully him or his friends, he will not back down and stands his ground. This has made him a hero to the moms whose kids have been bitten in daycare by a particular child.