S.F.
I wouldn't sweat it, power struggles end up causing resistance and refusal from little ones who are insecure with changes (in my experience with my 9 year old). Give it a month or so, play it (the big boy bed) up, keep it in his room, maybe even chose that as a special snuggle spot during the day at random for you two - so he can make a positive connection with that 'new place', maybe even say things about how you like your bed (daddy and I are going to bed in our 'big bed') and then try again about every 4 weeks, giving him the opportunity to adjust. Maybe he's just not ready to let go of the security of knowing what to expect. Sometimes I catch myself rushing my 2 year old, and then I remember (from having a 9 year old who's been through all of these big changes) that it's not forever, and it's really more about me wanting him to transition...but I've learned the hard way, that all things happen in their own time!! Don't worry - he won't sleep in the crib forever :).