So in all actuality, is the FBI really cracking down on music and DVD pirates? If I were to copy DVDs or download music, what’s the chance they’ll bust me?
IANAM–but the SDMB frowneth upon advising people on how to break the Law.
Be cool–stay in school. 
I think the factual answer here is that some people who break the law get caught… some people don’t. Is it worth the risk? How would an arrest conviction on your record look to future employers?
While there are certainly worse things in the world that you can do, modern society frowns on people who steal, which is basically what you are doing when you knowingly violate copyright laws.
I look at it as taking money out of the pockets of artists… who rarely get the biggest cut anyway.
It’s no vendetta: people are breaking the law, and the FBI is arresting those the find breaking the law. That’s their job.
The FBI tends to go after people who run large bootlegging operations – making tons of illegal copies to sell on the street corner or eBay.
If you use your mom’s computer to pinch stuff off p2p networks, you may just find yourself the defendant of an MPAA lawsuit, though.
The FBI is still ticked off about losing the treasure to pirates when their ship was boarded in the Dry Tortugas.
Not the FBI, but the RIAA has been pursuing music pirates on a more or less random basis. More or less random because they want to show that they’re going after everyone, not just organized rings.
Oh yeah, and music piracy is WRONG!
The FBI is primarily concerned with criminal violations of copyright law.
In terms of copyright violation, this entails one of two things :
Infringement that is intended for or results in financial gain (commercial use), or
Copying of material worth $1000 or more in a 6-month period (large piracy operation).
See here, Section 506 (though I can’t get it working right now).
Copyright infringement of other kinds is a civil matter, which results in a lawsuit, not an arrest. As far as I know, the FBI doesn’t (probably can’t) concern itself with civil litigation (though they might refer someone to the RIAA for such).
The civil lawsuits are what the RIAA brings when they aren’t sending pseudo-police squads after presumed pirates. The amount of money in these lawsuits can be rather high (though the usual tactic is to use this to force a settlement, still for a lot of money).
note : I’m not a lawyer.