We're having the same problem with our 2 year old.
I'll pass along our pediatrician's advice (and add that we haven't been very good at following it to the letter, but it does make sense).
He says that you should give the child his meals in courses, starting with green vegetable, followed by the protein, then starches.
If your son doesn't want to eat a course, that's the end of the meal.
The next meal *starts* with the last course from the previous meal. So if they didn't feel like eating their chicken at dinner, breakfast starts with last night's chicken.
If they still don't want it, wait until lunch.
He says that children won't starve themselves, and that his children all eat everything that's on their menu.
In honesty, we've tended to start working around both of our boys' preferences in ways that they seem to get a good, balanced diet that they enjoy, supplemented by vitamins (two different types for the 2 boys different tates).
Most parents I've talked to have had similar issues somewhere down the line. My guess is that you'll work up something that chides with your parenting style, yet still winds up delivering a healthy, well rounded menu to your little girl.
Good Luck!
-Scott (Husband to S.)