Currently it's my understanding that you MUST HAVE WinXP SP1 in order to get automatic downloads of CRITICAL patches to WinXP. If you get automatic downloads, IE7 will come with one of the recent ones.

SP2 for WinXP is strongly recommended, since it combines all prior patches, eliminates some conflicts between earlier patches, and equips you to continue to receive later updates.

Win2K is the only Windows OS, other than WinXP^**, that can receive automatically distributed updates. To get automatic downloads for Win2K you must have Win2K SP4 installed. With Win2K it depends to some extent how your machine is configured, whether updates can install themselves automatically or whether you have to do the installation step manually.

Whether you use another browser or not, Windows Explorer is an integral part of Windows and it MUST be present on your machine for Windows (any version) to operate correctly. For that reason, you should have IE6, with latest patches, or IE7 installed, even if you don't use it, and you need to install updates to your chosen IE - whether you use it for browsing or choose another browser.

All recent versions of IE allow you to turn off J-Script and Active-X, which are the plug-ins frequently cited as "vulnerable" when browsing with IE. IE6 makes it a little simpler to manage turning them on selectively in the few cases where they're actually needed. IE7 further simplifies managing them. All the other browsers that you can substitute must have the ability to use these plugins, and require you to manage them, if you're going to benefit from what they can do for you.

With IE6 you probably can still get the beta versions of popup blocker, bad download blocker, and possibly the anti-phishing plugin, but they're separate installations and sometimes puzzling to manage in that form. You also have to go look for them, if you think you want them. With IE7 these are all integrated, with appropriate management tools. From what I've seen thus far, they operate seamlessly and unobtrusively in IE7.

^** Server 2003 can also qualify for auto downloads of updates, but I'd assume those using it will know the details.

John