Hmm....I've thought long and hard (read: for maybe a few minutes while sipping a good IPA) about what my favorite shield might be, and I've realized that most of my favorite patterns (such the #15s and #92s, and the historic knives that inspired them) don't have shields at all. So I guess my favorite shield is most often no shield, on the right pattern of course. I just like them clean and simple, and nothing taking up more of the beautiful wood or bone than needed.
But on certain patterns, it just makes sense. In those cases - bombs, clouds, diamonds...it's all good, as long as it 'fits' with the pattern and isn't disproportionate.