What programs, websites or other applications leverage Mt Gox's API? I'm looking for sample programs and apps that leverage Mt Gox and learning what they do. Is there such a list in existence?  

Links to the appropriate BitcoinTalk or Wiki page would be more than sufficient as long as it's centralized.
Not sure of any official list but here are a few that I've found 

Github Repos


bitfloor books
bitcoin-arbitrage
metabit
mtgox-node.js-client


Websites


bitcoin charts
bitinstant