Cybercrime: $1Trillion in 2008

Rather a lot, really. You can discount this by quite a bit and still have a big chunk of change. This is what's attracting talent to the Black Hat community, and why malware is so much better than it was even 3 or 4 years ago.

“Cybercrime cost businesses an estimated $1 trillion worldwide in 2008, and some security experts believe the threat may be so bad that we may need to re-think our entire approach to the Internet.”

Via Bryon Acohido's blog, which comes recommended by SANS, which you don't see every day. Or ever, come to think of it. They have a good, free security "newsbites" email service, if that's your bag, baby.