What exactly is HARD to pirate?
edit: More specifically, Crack. I remember x-force having sources in all the major places ready to dump it to their cracker division.
I had links about about bypassing anti-debugging techniques, I'll see if I can get my hands on them again.
Those guys at Ableton are serious business.
Another popular, niche product that has proven difficult to fully crack is a program called Pro Tools, created by DigiDesign, now owned by Avid. It uses a protection called PACE Anti-Piracy[2]. Many expensive pieces of software require unique hardware, either a security dongle or some other external device.
[1] eLicenser.net
[2] paceap.com