I apparently voted "straight" here a while ago. So, update: it's now partially straight, and partially curly. I think about 40% of my hair has natural curls now, and the rest is still straight, although it has a slight wave to it. I've no idea what made it start curling itself, but I like it.
But it's such a thinned out, damaged mess now so I don't often show it in public anymore, but just stuff it in under a wig instead. So like on my profile pic that's not my real hair, but a wig.