My dd is a bit over 3.5, and has always been a high sleep needs kid. She'd nap for 3 hrs in the day if I let her, but then bedtime would be sooooooooo late, so I too limit her. Her day looks like this (usually):
7/7:30 - wake up
1/1:130 - nap
2:30 - wake
8 - bedtime
We do have occasional nap refusal, and on those days, she's in bed by 7:30. Sometimes she'll crash in the car when we go pick dh up from work, so she gets a catnap from 4:45 - 5:30 ish and is a total nightmare when she wakes up from that, so we usually still end up putting her to bed by 7:30.
I plan on keeping that nap as long as I possibly can. When she misses it, by about 4, she's just beside herself, and by 5, so am I!!