I know that toddler's bedtimes vary from child to child ... trust me, my friends and I all have very different bedtimes for our children (who are all around the same age)! ;) Personally, we've always let our children and their needs dictate bedtime (as long as it still stays early enough so they get enough sleep).
My daughter, who will be one the end of this month, is a terrible sleeper (especially right now). She has a hard time making it past 6 or 6:30 every night, and sleeps until about 6 or 7 the next morning. She doesn't nap well though, and is usually just dead tired by early in the evening. She's been teething terribly bad lately, and it's made sleeping (in the day and at night) a nightmare! ;)
My son, who will be 3 in February, has started staying up until about 8 or 8:30 p.m., but that's been a recent thing. He used to be in bed by 7 or 7:30. He'll sleep until 6:30 or 7:30 on average, as well. He also takes one nap a day (for about 2 hours on average).
So, they both get between 10-12 hours a sleep a night, with an hour or two naps during the day. I think children are unique though, and need different amounts of sleep. I found if I let my kids stay up too late, they end up getting up earlier in the morning and they are just cranky and sleepy all day! ;)
Good luck finding a bedtime that works for all of you. She may be going through something developmentally (with language, teething, etc.) that's throwing her off right now. Best of luck to you!