Most recently, at the 2011 North American Discworld Convention, my best costume was a cobbled-together Steampunk-Edwardian hybrid consisting of brown cargo pants, black lace-up boots, ruffled white shirt, tooled leather belt, purple and brown openweave coat, and a rebuilt brown hat with poufy veiling and brass rivet trim. The only things I made were the belt, the coat, and the hat. I got several hall costume awards.
The coolest sort-of-cosplay item I've made in a while is my TRON necklace, whipped up for the TRON 2 movie premier last year. Using an air-dry jewelry clay, I made a three-part crescent about 1.5"x8", with dimensional swirly 'carving' on the crescent and the toggle clasp. Then I covered the front of both with a very concentrated, professional-grade luminous paint. I sanded the top when dry, floated a little blue-green acrylic wash over all four pieces, varnished them, drilled out stringing holes, and put everything together with waxed tan linen cord and some glow-in-the-dark glass beads. In daylight, the piece looks like celadon porcelain. When charged, it appears to glow from within, in intense blue and blue-green shades. I wear it out to parties now.
I tend not to cosplay as a specific character, but as myself in cosplay-friendly universes. It sucks that the 2012 CostumeCon will be in Phoenix, and I'm not going to have the money to go.