I have to say Don't Care, mainly because there's no "Both" option. Both could work, and it'd be phenomenally simple - texture-wise, at least.
Just have an option in the Graphics Menu to switch between Square and Round Sun/Moon. I mean, we have options which do Smooth Lighting and for Field-of-View, and for this all it requires is two textures in the Texture Folder. Now, I won't pretend to understand any programming, but it seems this would be fairly easy to implement.
Besides, here's the real kicker. Going back to what I said: You all can change the texture of the Sun and Moon to whatever you want. For crying out loud, it's easier than installing a mod. I honestly don't see why everyone is getting into a fit over this.
But yeah, I'm supporting both.