my favorite three as animal transformations go are
1. Cow girls (I also love BE and usually happens with this transformation so double +)
2. Cat girls (sometimes involves BE, but cat girls are just classic TF
3. Bunny girls (no BE, but hey can't beat a permanent playboy bunny
.)
Least Favorite
Dragon (not into the muscle girl look and most of the dragon pics make them look creepy rather then sexy.)