1. Eowyn's white dress. The one she's wearing when we first meet her. Whenever I think of LOTR costumes, this is the first one that springs to my mind. I love the swooshy sleeves, the drop-waist belt, how simple and elegant and, well, princess-like it is.
Sadly, it's kind of hard to get a clear, full-length shot of it from the front. Which is annoying, because one of my favorite things about it is the long, intricate belt that hangs down the front.
I also like the neckline. I don't like V-necks usually, but this one is so wide it's pretty instead of sporty, and the embroidery around it is gorgeous.
2. Boromir's everything. I completely adore his entire outfit. And there's a lot to it! Big boots and some kind of pants we don't see much of, chain mail, and a beautiful, princely, burgundy... surcoat? I'm really bad with names of clothing, especially period stuff, sorry. And over all that, a long, sleeveless, leather coat thing that looks so supple and yet tough. And when he arrives in Rivendell, he's wearing a very luxurious fur cloak. Plus his wonderful leather gauntlets, leather gloves... there's no piece of this costume I don't find amazing. I wonder how much that costume weighed? It certainly bulks Sean Bean up a lot -- he looks quite beefy and stalwart, when I know from other movies that he's actually kind of... not beefy.
When he's in Lothlorien, he trades the fur cloak for a grey Elvish one like the rest of the Fellowship. Here's some detail on his sleeves, all embroidered and fancy.
Hand-stitched gloves, with a nifty buckle closure. Mmmm, I love those gloves. I have a thing for gloves, though.
I don't know if you've ever noticed this, but after Boromir dies, Aragorn keeps his gauntlets and wears them from then on.
3. Bard's gloves and coat. The coat is awesome -- it's so unfinished! The edges aren't finished in any way, the sleeves are too long, and altogether it's screaming "this is good enough, and it's all I've got." It also looks warm and comfy. I want one.
I positively adore how he's cut slits behind the sleeves to give himself better range of movement. So practical. That's one of the things that makes me love Bard: he's always very practical.
And then there are his fingerless "gloves." Which I think are almost just fur pelts turned fur-side in, with holes cut for the thumbs and something to keep them closed. Again, crazy practical, with a "best I can do" aura. I want these too.
4. Galadriel's shimmery dress. The one she wears when we first meet her in Lothlorien in FOTR. It's so ethereal, like wearing starlight. And it has a train/cape thing, which seems to be detachable.
See? No train/cape thing later on:
Look at all the intricate detail on this fabric! Do you think that's beading? Are they supposed to be Elanor or Mallorn flowers, do you think? They make me think of snowflakes.
5. Strider's Ranger clothes. In the movies, I prefer Aragorn when he's all grunged up, in his Strider look, rough and ready. Everything he wears here has a practical purpose. (Yeah, I've come to realize I love practical people and things. Bard's responsible for that realization. Thanks, Bard!)
Also, long black coat. I am a huge sucker for long coats, especially black ones. Love them on almost anyone.
6. Thranduil's cape. I really wish I had a good picture of him arriving on his elk, with his cape thrown back over the elk, looking so regal and fabulous. You can see it a little here, which is the best pic I could find online.
7. Tauriel's green jerkin/coat/thing. It's the most gorgeous color ever. Also, it looks like it would be kind of fun to wear. And it makes me think of Robin Hood.
8. Arwen's red dress. We don't get to see it much in ROTK, and I ran out of time to find that one scene and screencap it, so we must make do with something snurched off the internet:
Those sleeves! The embroidery! The color! Delicious.
(Runners up would be Bilbo's cape at the very end of TBOTFA when he returns to the shire, Elrond's armor in TBOTFA, and Bofur's hat. But this is really long, so I'll quit here.)