our 3 yo. just recently decided he was done taking naps and WOW what a difference it made in bedtime. he also was taking an hour or longer to get to sleep and not actually falling asleep until 9:30-10, all the while insisting that i sit right by his bed as well. now with no nap i start the bedtime routine around 7 and he's asleep by 8, he does still insist that i am at least in the room (his bed is in our room, so i can lay in our bed and read), but after reading 1-2 stories and getting him tucked in he's usually out in 10-15 min.
i'm due with another one in feb. and as much as i didn't want to give up naptime (it was MY naptime too!!) as well as dealing him being a little crabbier sometimes in the evening i decided it's way worth it for DH & i to have our sanity!
as mentioned already ds decided on his own that he didn't want to nap anymore, so maybe yours is right on the cusp of giving his up too and while i'm not suggesting you take your lo's nap away maybe you should discuss it with him