They have the best security feature of all - the Mac effect. Virus writers don't bother too much with the mac because of the smaller user base (don't believe any of that nonsense that it's more secure - as we've discovered this week it's not). If their virus doesn't make front page news, can only affect .0005% of the computers out there, and have no impact on businesses where's the glory in that?
Already a lot of security risks are XP only risks, despite NTFS. Know any Windows 98 PCs that were affected by blaster?
Stick with 98 (especially if you have 98SE), do your regular housekeeping tasks like scandisk and defrag so you don't suffer PatrickDeese's fate (whose machine not crashing now is only partly XP - but probably mostly because it's a clean install of the OS without clutter). Soon you'll be laughing as virus writers concentrate on bringing down Linux, XP and Windows 2006 machines :)