It appears 2010 has been a cracking year for malware developers. Customised malware is a significant threat to any environment, given the fact that controls that can effectively protect against these attacks are limited and difficult to implement. Anti-virus certainly does not provide much protection against a trojan that has been customised to attack a specific organisation. FUD is a term used in malware circles and referes to "Fully Un-Detectable" by AV.
According to PandaLabs 2010 Annual Report:
"In 2010, have created and distributed one third of all viruses that exist. These means that 34% of all malware ever created has appeared -and been classified by our company- in the last twelve months." 
They have noticed a rise in malware distributed via popular social media like Facebook and Twitter as well as Linkedln and Fotolog. Activist attacks have been on the rise as well including coordinated DDoS against popular websites in support of Wikileaks. PandaLabs believe that most of the trends of 2010 will continue in 2011 including;
"[...] an increase in the threats to Mac users, new efforts to attack 64-bits systems and new zero-day exploits."