Well, I'm not sure how much linux experience you have, but I really like Slackware. IMHO, it doesn't feel windowy (new word) like RedHat does. RedHat is good..don't get me wrong, but the fact that it isn't free anymore, kinda turns me off of them. I mean you can still download it and install it, but I coming next year, they are stopping support or errata for their previous releases.

I'm starting to play with SuSE a bit, so I'm curious about that myself.

In terms of security, I agree with you saying that it's knowledge of the person securing the box, but the windows operating system and its applications seem to have far more security holes than any of the linux flavors.

You could always dual-boot

Hope I helped.