I like the Ice planet with 4 crystal asteroids the most, always good to have it, and it feels good, I don't know if you can understand my last though though. And I like the Pirate Base as a planet (so completely clear of those pirate stuff like mines, turrets etc), because it always makes me remember that it was a moderate fight getting it (I always steamroll it with a late game fleet and a titan to maximize my efficiency), and it is funny to have it as a normal planet like a terran or something
, though I always feel like missing something as it has no resource asteroids, and I always build some turrets to have something around it.
Just a last thought on the Ice planet, I really liked the texture that had huge ice valleys on it, giant ocean frozen and getting broken, the current one is good, realistic and stuff, but that one was so awesome, and they removed it... was a huge disappointment, I though they will add new textures, not just one new, and removing every other one...
In mods I don't have a favourite planet type, most planets are unbalanced or extremely weird, greatly ruining my gaming experience, and it is a sad thing. Or I just don't like that mod having new planet types to have a sense of those (like distant stars).