Below is a collection of the top costumes on the web. This list is the result of my attempt to assemble a catalog of giant, awe-inspiring costumes.

I don't claim for this list to be perfect. A million costumes have been made for stage and movies and the Olympic opening ceremonies and none of them are on this list. Full disclosure: five of my own costumes are showcased below. Is that against the list-making rules?

Kevin Kelm's Mecha costume.
http://triggur.org/costume/mech

The web page for this nine-foot wolf robot includes well-written construction notes.

More of Kevin's costumes, including one with a carbon-fiber helmet and electronic circuit schematics at his costume site:
http://triggur.org/costume

Functional Iphone Costumes
John Savio and Reko Rivera's functional iphone costumes.

http://forums.macrumors.com/showthread.php?t=808676

Big Daddy from BioShock video game
http://volpinprops.blogspot.com/2009/09/big-daddy-bioshock.html

This monster is the incredible work of Harrison Krix, a propmaker out of Atlanta. Excellent write up of his construction techniques. He doesn't do anything half-assed.

He has many other builds on his site, each more incredible than the last.

http://volpinprops.blogspot.com/2009/10/daft-punk-helmet-part-2.html

Lord of the Rings: Sauron
http://www.flickr.com/photos/9639428@N03/3905235010/

Speeder Bike and rider
http://www.studiocreations.com/howto/speederbike/index.html

A very cool illusion beautifully rendered.

Centaur
Laecee R.

http://www.coolest-homemade-costumes.com/coolest-centaur-costume.html

This article was nearly re-titled "Awesome costumes for MEN", but lo! There are women who make supersized costumes too.

AT-AT costume
Matt and Christi

From Dragoncon 2009

2-man AT-AT costume
Jason

I believe this was in New York City.

AT-ST costume
Cheston Botso
http://my350z.com/forum/the-lounge-off-topic/391776-my-halloween-costume-2008-star-wars-at-st.html

Cheston's got a number of pretty good build logs on his site.

Ring Wraith with Hobbit in a cage
Earl Bergquist

http://www.boneboy.com/costume/02hbcg.html

This is probably the only actually scary costume in this bunch.

Alpha Flight Sasquatch
Allen Hansard and Beau Brown

http://www.thesuperherocostumingforum.com/topic/890/t/Sasquatch.html

Iron Giant Costume

This stilted giant won the top prize at the Industrial Light and Magic halloween party in 1998.