The difference is that Windows is riddled with hundreds of remote exploits that require no user interaction
No, malware on windows requires user interaction, same as OS X. To pick up a virus from a network segment you'd have to have enabled file sharing with open rights or something equally stupid. Good anti-virus also mitigates this risk.
OS X annually has many many exploitable bugs, until recently nobody has bothered as the market share for apple has been insignificant. Now the malware people are looking at apple users as easy pickings as they typically have no AV software. Why do you need AV Software? Because there is a lag between exploit and the patch, and apple are notorious for keeping quiet about these and being slow to patch (whereas microsoft are quick to respond due to bad press they get).
So you plugged an unpatched XP box with no AV directly into the net and got infected - if anything that proves my comment about users.
So, let me re-iterate, the same methodology requiring user interaction on OS X malware is used to infect Windows systems. Malware does not rely on exploits to infect systems, it relies on social engineering. OS X users have no AV safety net, windows users usually do. It wasn't even until 2009 that Safari got phishing protection of any kind.
As for the hardware comment, bollocks. I see this problem with mac's all the time - it may be what the sell you but it sure ain't reality. Want your 3G card to work with a Mac? Gotta install the 3rd party driver. Want your Mopier to work with your Mac? Gotta install the 3rd party driver.
In the last few years I've seen more Mac's brown screen than I've seen PC's blue screen. Mac's are nice, but they have their share of problems (look at Snow Leopard for that LOL).