What would you not want to touch 11.04 for another year? The damn OS is only supported for 18 months and it has been out for four months and in another 12 months means you would only have support for 4 months. Also it does not matter which which version of Ubuntu you use, 99.9% of Viruses/spyware/Malware is on Windows and does not exist for Ubuntu. This is for the fact Ubuntu being Linux it is more secure and secoundly the OS commuinity may be large for a Linux community and is the third largest OS but in reality it is still kind of small which means less interest from the people who make the Malicious code.