If you have the time and tools to make your own Halloween costume, all you need is a little inspiration to make it awesome, like these ten. Note: these are presented in no particular order. They all rank #1 in my book!
1. Big Daddy
Graphic designer Harrison Krix made a costume of the character Big Daddy from the video game Bioshock. This is a work of a serious propmaster. It took seven weeks of sculpting with foam, cardboard, and fiberglass. The finished product, complete with a working drill arm, is a work of art. The post includes many more pictures and a couple of videos of the drill arm in action.
2. Yip Yips
Sesame Street's popular aliens, the Yip Yips always appear in twos, so this is a costume that should be worn with a buddy. It take two people to properly fit one according to this Instructable, so you may as well help each other out and into a great costume!
3. Optimus Prime
Instructables member dannyeurena turned cardboard, duct tape, and hot glue into a satisfyingly authentic Optimus Prime costume. According to the accompanying video, it was comfortable enough to dance in!
4. Death Becomes Her
Evan Booth's costume for Halloween 2006 seemed to be a nondescript "dude in a wig" until you looked at the GAPING HOLE in his midsection! This was accomplished with a camera in the back of the shirt that recorded a background scene and fed it to a travel-size DVD player in the front that displayed the backdrop. In 2008, artist Nicole Magne used the idea for a costume recreating a scene from the movie Death Becomes Her where Goldie Hawn has a hole blown through her body. The creation process is detailed on her blog, and the Instructables version is available if you'd like to try this yourself.
5. Hovering Boba Fett
Linkfilter member Reapre had considered a Rocketeer costume when he hit on the idea of Boba Fett Hovering on a Column of Flame. He used a purchased Boba Fett costume and converted it using a homemade jetpack. The column of flame below hid his legs. Reapre wore platform shoes made from roller blades to make himself several inches taller.
6. Iron Man
7. Helmet Cat
Flicker user Alida Saxon's brother put this Helmet Cat costume together at the last minute. The helmet is a basketball painted green, and the fur was salvaged from a stuffed toy. Make your favorite internet meme into a Halloween costume and half the folks you encounter will laugh; the other half will scratch their heads and wonder. See also: keyboard cat.
8. The Wild Things
A group of five friends dressed as the monsters plus Max from the Maurice Sendak's book Where The Wild Things Are for Halloween 2008. Craftster member sjeanette made papier mache heads of the monsters. The eyes glow in the dark! I can't really tell how one would see while wearing these, but I assume they made a great impression.
9. Mega Man
Kevin made a Mega Man costume for his 3-year-old son last Halloween. What made this so awesome is the Mega Buster with working lights and the authentic helmet fashioned from a bike helmet. See more pictures of the finished product.
Rob at Cockeyed.com is known for (among many other things) his 2004 Dr. Octopus costume. It was not his first project involving a costume that dominated the room. In 2000, he won a costume contest by showing up as the Paparazzi, meaning, all of them! He collected camera shells, soda bottles for the flashes, and masks from which to make the faces. The working flashes were wired to a switch he controlled, so there was no way to miss his entrance.
Not exactly homemade, but worth a look! The Mask of Emotion hides your face but displays Asian-style emoticons instead. This helmet was created by the Digital Media Design Dept at Hongik University in Korea. What emoticon is shown is controlled by the wearer's body actions. If you want to make your own, the original website has design specifications and video. It will help if you can read Korean.