According to a well respected security firm, Microsoft's flagship Windows 7 operating system is less secure in its default configuration that Vista.
Trend Micros CEO Raimund Genes believes that Microsoft has put usability ahead of security:
"I'm not saying Windows 7 is insecure, but out of the box Vista is better."
"I was disappointed when I first used a Windows 7 machine that there was no warning that I had no anti-virus, unlike Vista. There are no file extension hidden warnings either. Even when you do install anti-virus, warnings that it has not been updated are almost invisible."
"Windows 7 may be an improvement in terms of usability but in terms of security it's a mistake, though one that isn't that surprising. When Microsoft's developers choose between usability and security, they will always choose usability."
Interestingly, Genes believes that the XP Mode feature present in some editions of Windows 7 actually improves security because it makes available a sandboxed OS. Other security firms (in particular Sophos) have criticized XP Mode, labeling it a security risk because it needs to be patched separately.
So, for a more secure Windows 7, Trend Micro recommends upping your UAC setting higher.