I know the general gem most creatures will fill, and that is not my complaint. My complaint is that when I am trying to fill gems to enchant items I don't know when I've filled up all of my petty/lesser/common/greater. I kind of get annoyed when I check my inventory and see a bunch of my Grand Sould Gems with petty souls. I really don't like having to check my inventory every other soul I capture.
My request is very simple: When it says 'Soul Captured' tell me what soul gem was just filled. A very small and simple suggestion.
Would anyone agree with my idea? It would not take much to incorporate into a patch.