Windows updates vs linux (any flavour)
The talk about the number of updates between the two systems, and the relative security offered by both need to be looked at in context.
Take two machines...
1) Install the standard WinXP (first release, not SP2, which was basically a complete re-write - or for that matter, use SP2, it still has holes) - DON'T use a seperate firewall, virus checker, or spyware detection, and don't bother updating - most users are still too dumb to bother - if you're really brave (should that be stupid?) try browsing a few salubrious sites.
2) Install linux (pick a flavour, any flavour). Don't update etc as above.
Stick both online, and see how long they last before they're completely owned by an unknown third party.
Going back 2 years or so, the lifespan of a "virgin" XP box was down to about 8 seconds of first being connected to the internet before it was well and truly rogered and turned into someone elses' bot-bitch.
If the linux machine lasts more than that, you have your winner.