This chess board built with Lego Mindstorms is amazing. The group that built it has lots of information about more information about building this on their website.
Bricks of the Dead is a webcomic about zombies using Legos for visuals,
ChromeBricks.Com sells Lego minifigs and bricks that are chrome and gold plated. Like this nice C3PO minifig.
Personally, I think Stargate SG-1 is one of the worst science fiction shows ever, but this gigantic Lego Asgard Beliskner Battle Ship being sold on E-Bay is amazing. Tens of thousands of Legos there, and only $3,500 for the lucky SG-1 fan.
Fine Clonier Decals sells custom decals for Lego minifigs. Each decal costs about 50 cents, and they have everything from superhero-themed decals to World War II.