I always imagined her to naturally have tan skin

Too many people believe she'd be African-Anerican. Even my friends agree all the Mane 6 would be Caucasian, because you can tell by a person's accent or voice styling. And Twilight's and the others are that of a Caucasian voice. Not trying to be racist, so sorry if I offended anyone.

I imagine her as mixed between a white race and a black race, resulting in a tan skin colour. Personally, I kind of headcanon her as part Caucasian and part Indian.

Remember that not all black people are African-American and not all white people are Caucasian. There are are lot of races with black skin tones and a lot with white skin tones, so there are a lot more choices when thinking about these things!

I can imaging Twilight Sparkle's genderbent form being an African American, so that's why I chose this. XD

I headcanon her as African American, but I also like Indian and Asian Twilight.

Why do you all think she's Indian or African American?!? And yes, I know there are a lot of races in the world that have white and black skin.

Well, it's just my preference. They're ponies in canon, and even when they were human they didn't have natural skin colors (purple, pink, etc.) so it's up to the viewer individually to decide what they like.

I always think of human Twilight as Caucasian.