We went straight to the twin bed (w/bed rail.) We also have a convertible crib - so you can convert it to the twin/double bed for your second child rather than for your first. A twin mattress/box spring plus bed rail (plus waterproof mattress pad and bedding) was still cheaper than a new crib (plus double the amount of crib bedding.) But definitely do it very soon - the more time that has passed since your son was last in the crib before the baby gets here, the better. If you can, put the crib AWAY (attic or basement) until right before the baby is born. We talked up the "big boy bed" for a few weeks, and then he came with us to pick out the mattress, sheets, etc. (He was 2-1/2 when we moved him into the twin bed.) He had also not ever tried to get out of his crib. One suggestion, depending on room configuration: we put his twin bed in a corner, and put a bookshelf at the foot of the bed, so he still really had "four walls" like in his crib. We figured since he was still pretty happy in his crib, it might make him more comfortable. We did end up lying with him until he fell asleep for a few weeks (which, in a twin bed, is of course not so hard, you just get in bed with them) - but that was pretty easy to transition out of once he made the adjustment. The one thing that surprised us was that, rather than getting himself out of bed when he woke up in the morning, he would call us, just as he had when he was in the crib - even though as soon as we came in the room he would then climb out of bed by himself (with the help of a little stool.) It's taken him a long time (almost a year) to leave his bed without calling us first. (Although I know some parents would pay money to have a child who stayed in bed like this.) Good luck!
