-brentg33
Try to remember this: OS X is based on a Unix variant e.g. designed to be on all the time, debugged ad-nauseum, and secure as priority #3 (the former are #1, and #2).
Windows, even Vista, is built upon a codebase (yes, it's diminishing with every version, but it's still there) that had no concept of the Internet. So security, despite recent attention, is still a fundamental issue. It's not arrogance per, se, it's just that was the thinking at the time, and they've just moved the code forward.
That being said, spyware, virii, trojans, worms, et. al. are just not as easy to write to any kind or effectiveness for OS X. Sure, nothing is invulnerable, just tougher than others.
So you really, honestly, don't have to worry about it right now.