My DD1 also started having crib parties up until 10 or even 11 some nights just after her second birthday. She was at the time taking a THREE hour nap, though, so really, it's no wonder. We needed only to trim it to 2 hours, from 12:30-2:30, then put her to bed at 8:30. She'd wake at around 8 am or so, too. She'd always needed a bit more sleep than average.
She is now nearly 4 (will be in September) and still napping most days, from about 1:30-3:30, though she wakes closer to 3 some days. She goes to bed at 9 or so and is asleep by 9:30 most of the time (sometimes stalls until 9:45, though).
Honestly, for us, even though it means a later bedtime, I much prefer keeping the nap for as long as she'll take it, both for the break for me, and the fact that she's a wreck by 7 pm if she doesn't nap and goes wild, hitting her sister, being very disagreeable, etc. When she used to skip her nap before age 3 and 3 months, she'd have NWings, too.
I say keep your siesta and go with a later bedtime if that's what works for you. My relatives in Israel all follow this pattern, with everyone taking naps at mid-day and then staying up late in the evening-- it wasn't uncommon to have young kids up as late as 10 pm as a matter of course. As long as your DS is getting enough total sleep (I'd say about 12 hours is right-- I think 11 hours is too little for the vast majority of kids this age) and sleeps well when he is sleeping at night, then by all means do what works for you!
