I've been running IE exclusively since 1996 (before that I used Netscape 3) and have NEVER had a virus, spyware, or other malware infestation (and never had any attempt at infecting me that I would not have had running any other browser, meaning a piece of software trying to install itself that happened to have been infected, this kind of infection doesn't depend on a particular browser).

My secret? I know what I do and don't visit warez sitez, I don't use Kazaa and other P2P programs to get pirated music and software, and I don't click on links to sites I don't know in banner ads.
I also never open email attachments I didn't expect to get and kill all email I don't trust on the server (or have it killed by my spamkiller and email virus scanner).

It's not IE that is inherently insecure, it's the people using it. Were those people to use another browser they'd still click "yes" when asked to install Kazaa or RealPlayer or some download accellerator...