pluto
Since what used to be my favorite planet is no longer up for consideration, I guess I'd have to go with Venus. I think all of the other planets are pretty neat in their own ways, but Venus always stands out as so close, yet so foreign. It's one of our next door neighbors, and so similar to us in some ways, but sooooo very hostile and different in others. The thought of that planet makes me feel all cosy and safe here on earth. For now, at least.