I thought that the Wooden Shield and its upgrades (especially the Braced Shield, love that one) look pretty cool. I don't know why, but... eh. I liked them.
As for the Iron Shield and its upgrades, it's unique to say the least. I think a rectangular shield was pretty cool looking on Link, albeit a bit weird since I'm accustomed to seeing shield-shaped shields on him. It's was cool, but ultimately I'd prefer shield-shaped shields and circle shields.
The Sacred Shield, in its un-upgraded form, I think is quite cool-looking. The Divine Shield is okay, but I didn't really like the Goddess Shield aethsetically, or having Hylia stare at me from the Sandship to the Song of the Hero parts. It's too much of a... depiction, in my opinion. Yeah, it's a unique design, and while I don't necessarily dislike it, I can't quite say I like it.
Of course, the Hylian Shield looked awesome, as always.