Bitcoin code was used for Namecoin, which provides decentralized DNS as well as decentralized CA (credentials free of any certificate authority.)
Bitcoin can be used for proving notice. (Replacing say, newspaper classified ads for the same purpose.) Bitcoin will become the ultimate notary.
Bitcoin makes it possible to wire gold. For example, you walk into a gold shop and hand him some physical gold in return for BTC, which you send to your grandma in Asia. She then walks into a gold shop in Africa and leaves with physical gold.
...Thus, Bitcoin can be used for wiring anything.
Bitcoin, via colored coins, makes it possible to issue real-world assets without having to trust a central entity to control the ledger.
Bitcoin makes it possible to run exchanges anonymously, at a profit.
Similarly, Bitcoin makes it possible to operate bazaars anonymously at a profit. (Silk Road being one infamous example.)
Similarly, Bitcoin makes it possible to operate prediction markets anonymously at a profit. These have the potential to drive scientific progress as well as political change.
...Basically, Bitcoin makes it possible to operate many many things anonymously at a profit.
Bitcoin makes it possible to eliminate capital controls. There's the basic concept of using Bitcoin to move funds across controlled borders, but it goes much deeper.
...For example, let's say that there are capital controls in Argentina, which drive up the Bitcoin price to 130% of its price in the USA. This means that a beef exporter in Argentina, who prices his beef in Bitcoins, will be able to undercut all the other Argentinean beef exporters by 15%, while simultaneously earning 15% more money for his sales. Therefore Bitcoin is destined to eliminate all capital controls.