[PYroMaNiaC]

You've said that he seems to sleep well during the day. He even looks forward to naps. Could he actually be afraid of the dark? or at the very least, scared of waking up alone in the dark? Install a dimmer switch and when you put him to bed, leave the lights on. Gradually, over the next six months turn the lights down when you head to bed.

Or it could be that hes very sensitive to the fact that he can hear Mom and dad puttering while he naps and therefore knows that Mom and/or Dad will be up and about when he wakes from his snooze. You can try the white noise machine, but it's just as easy to turn the monitor around and put the listening end in his room and keep the noise end with you. If he wakes up in the middle of the night, he'll hear you moving, snoring, breathing and know that you're there.

Finally, kids can need naps until 6 or 7 years old. I used to sleep on the bus ride home from school. All that play and learning makes for tired children. Do not remove the naps. Heck, if he's that over-tired at bedtime, give him two. One about 10:30am until noon and another about 3:30 till 5. It never hurts to try something unusual anyway.