The term "hacker" can refer to a lot of different types of people.
On the one hand you have the criminals, breaking into digital vaults to steal information that they hope to turn into money - whether its credit card numbers, personal data or compromising photos of celebrities.
Then you have the nuisance groups like LulzSec, which break into and attack systems purely for shits and giggles. They don't steal data, just disrupt and annoy.
Move one step to the left and you'll find the so-called benevolent hackers, which come in many varieties: there are the security hawks that try to break into systems just to prove that they're vulnerable, who then share that information with the system's gatekeepers so they can beef up their protection.
There are the truth hackers who use their skills to bring information to light, some of it that might be embarrassing to companies or individuals. The collective know as "Anonymous" are among the most prominent "hacktivists" on the network these days, sometimes using their abilities to aid protestors in countries like Iran, and sometimes targetting people and organizations that they feel deserve a kick in the virtual groin - like Sony for its harmful DRM software or white supremacist Hal Turner.
Then there are the open source hardware and software hackers, who believe that once they've purchased a piece of software or hardware - like a phone or the Kinect - then they should be free to do whatever they want with it, whether it's jailbreaking an operating system so they can use their software of choice or adapting a device for another use. These guys are my favourite hackers, and some of the most creative people in technology today.
Most ominously, we also have what can only be referred to as state-sponsored hackers, online spies that are in the employ of governments or companies with ties to government. It's this type of hacker that is making the news these days, with attacks on the CIA, prominent American defense contractors, prominent American companies like Google, and so on.
The nature of these attacks make them difficult to track, but there's evidence that a lot of it originates in China. The Chinese government denies any of it of course and claims that rogue elements in that country are responsible rather than the state, or that the accusations are baseless and were created to discredit China.
Some people aren't buying it. In his recent column in the Wall Street Journal , Richard Clarke suggests that China is far from innocent and is using cyber espionage to advance its own military technology and its hegemony over technology manufacturing.