My favorite is the Cody bust. He comes with a holographic emperor! That is sweeeeeet. Gree has the coolest armor in my opinion so he ranks right up there with Cody. Of all of the busts I now own I have to admit that my favorite may be the Shocktrooper.
The coloring detail and battle-damaged look are awesome. I have a tough time picking my favorite type of trooper. I usually jump back and forth between the Shocktrooper, Utapau Shadow Trooper, and the 212th Attack Battalion.