I like the different techniques and Kixum's tutorial is very good and detailed.  I have done planets in Poser and Vue and decided to do one strictly in Carrara 5 Pro (okay, I did post work in PaintShop Pro-eg atmosphere and starfield).  The planet texture is made from  earth textures that have been cut out rearranged and pasted back in via PSP to get a totally new planet terrain.  Jan