@SP Its the process, not the proceeds, that constitute the crime, surely?
Release into the public domain of information about an individual - that would be hacking. Distributed Denial of Service- what anonymous are doing to the WBC site at the moment - thats illegal,since it prevents the WBC from receiving the service from the ISP that they have paid for. Others have hacked systems and released information on passwords, for instance, or bank account details. All these represent a breach of privacy and are therefore illegal, I would have thought.
You might occasionally see a hack where the hackers are claiming a public interest defence - highlighting security flaws in Operating Systems, for instance, or the release of classified intelligence data, as in wikileaks - but those actions would still technically be illegal.