Don't abandon the PDF file format, but also don't place undue trust or confidence in it. Malicious attackers will prey on that trust. Also, make sure you keep Adobe Reader up to date to take advantage of new security controls introduced by Adobe, and ensure that any known vulnerabilities are patched.
It is some sort of poetic irony, I suppose, that the February 2011 Intelligence Report is in PDF format itself. Seems like a bizarre paradox for the security report alerting me to the dangers of PDF files to be distributed as a PDF file.