Kite: Or oval. A good early medieval design, but not one for the later periods. I still like it if only because its size is great for making stickers (and you can get cheap Islander/Amerind shields). This is the one that got my vote.
Heater: Or triangular (but see below). That funky hand grip! I usually have the figs carry the shield at the low port gripping the horizontal bar rather than have to do the full arm extend with the vertical bar. It shows off the torso design better with the former grip.
New KK: Just a placemarker comment for when I actually see it. Looks kinda more Roman than medieval, but we shall see.
Trash Can Lid: Sometimes refered to as the "round" shield. I think I've summed up my opinion as to what it looks like. Dull as dirt gray and the "corrugated" trash can lid look is not conducive to stickers.
Asian Convex Round: Alas, you can't easily put a sticker on these, and they are rare, but they look good.
Interesting alternatives:
(real) Triangle: Why Lord of the Lego refers to this as Roman, I'm not quite sure, but either as a single or double to form a diamond shape, it's a interesting change of pace. You can put a sticker on either format.
Round Radar Dish: Chop up a Harry Potter Wand to make it shorter and it becomes a grip and a shield boss. Forget stickers, but at least it has a variety of colors. A good make-your-own.
2x2 Round Flat: Or what do I do with all these yellow targets that I got in one of the castle accessories packs? Slap a sticker on 'em and mount with either a round dot or a beer tap (glue helps because otherwise the arrangement is fragile).
2x2 Round ship bottom piece: Gad, what's the proper technical name for this one? It's the convex piece that is usually put on to the bottom of Lego ships so that they slide easier. I press these on to Skeleton arms so that they hold their "shield" to the side. Considering the floppy and fragile nature of Skellie arms, this actually works reasonably well.
