This magic SIM card from SK Telecom is a long way off from being commercially viable. But so help me, when someone stuffs this much information into a single SIM, I'm going to stand up and take notice.
Packed into this protoype are a processor, memory, 1GB flash storage, and Android OS. That's enough to keep your entire mobile world into one SIM, making switching phones the simplest thing in the world. You could also use it to easily switch off information between your handset and your netbook.
Of course, it also means that losing your phone would come with its own additional host of problems. Though by the time this would actually be available, it's likely that all your most important stuff would be in the cloud anyway.