Our little boy takes 2-3 hours to fall asleep every night. He settles really well about 7pm after his bath and story routine, but about 20 minutes later starts talking to himself, playing with his toys and kicking his feet against the wall. This goes on usually from 7:20 until around 9:30 at which point he falls fast asleep until 7 o'clock (to the minute) every morning.
This has probably gone on since about 10 months old - which is when we figured out just to leave him to go to sleep. Up to that point, we barely slept more than 2 hours, but since then he's been a good sleeper.
Really interested to hear everyone's views on this as I've never seen it in any comments or websites - the closest thing I've seen is some research on Crib Talk, which definitely seems part of what he is doing, but generally for up to 30 mins, not 2 and a half hours!