I think that the best works of fiction incorporate both Starfish aliens and Rubber-Forehead aliens. One mustn't discard the possibility that other intelligences might evolve in a fashion analogous to us, but rather incorporate the knowledge that we cannot foresee every possible form thereof.
For logical consistency, if there are both rubber-forehead and starfish aliens, then the starfish aliens should be separable into groups, such that all species in any given group are rubber-forehead aliens relative to each other. Instead of (say) three sets of rubber-forehead aliens and three sets of starfish aliens that are starfishes to each other as well, it seems more reasonable to have three sets of rubber-forehead aliens and a number of similar clusters of (approximately) four species each consisting of remarkable similar starfish aliens. (If they're starfish enough, then humans might be unable to differentiate between their species, and that's fine too. They might have just as much difficulty telling humans and ferengi apart, after all.)
I think that the best works of fiction incorporate both Starfish aliens and Rubber-Forehead aliens. One mustn't discard the possibility that other intelligences might evolve in a fashion analogous to us, but rather incorporate the knowledge that we cannot foresee every possible form thereof.