This has been so interesting to read - thank you to everyone for sharing your experiences!
DS will be 3 at the end of this month. He currently naps most days a week, but some days just doesn't fall asleep. I still nurse him to sleep for naps, so I usually try for about an hour, and if he's not asleep after that long, I give up. If he doesn't nap, he usually gets a good 12-13 hours of sleep that night (maybe 8pm-8am). However, if he does nap (maybe 1 hour long), he usually only sleeps about 9-10 hours at night (maybe 11pm-8am) - so he actually gets more sleep overall if he doesn't nap. But, as someone else mentioned, our late afternoon/evening is pretty limited if he hasn't napped, since I know he'll fall asleep if we go out in the car or for a walk in the stroller. As well, he doesn't sleep as well - he usually wakes up an hour after I put him down (on no-nap days), and maybe once more in the middle of the night. On days that he napped, he usually sleeps straight through without waking at all.
Anyways, I'm glad to hear that DS is at least in the average range for amount of sleep on both nap and no-nap days. I've been debating dropping his nap, because he does seem to sleep more and it's nice to have him in bed earlier. But, I do think sometimes he needs that mid-day snooze (and he does fall asleep fairly easily at least 3-4 days a week). I've recently tried to make his nap shorter - I nurse him to sleep, and then move him to our bed. He usually wakes up around an hour later, and I used to nurse him back to sleep and let him snooze on my lap for at least another 1-2 hours. Now I try to avoid nursing him back to sleep, so his nap is only an hour long. Some days it's fine, other days he is miserable and I have to nurse him to extend his nap a bit - but at least it's a nice intermediate approach from one long nap to no nap at all.
Anyways, sorry for rambling - but it was great to see other people having a similar experience to us!