On the Windows XP on an antique tip -- I had tried an upgrade from ME. That mostly worked but there was something effed up about it that wouldn't let the Echo Mia drivers install. So I reformatted the partition and installed from scratch. Nothing like the minty fresh feeling of XP when you've finally got it all patched and tweaked the way you like it, before you load it down with hax0r shit.
Speaking of which, Mozilla Firebird Browser and Thunderbird mail reader work great. I even did the "Set Program Access and Defaults" thing and hid Internet Explorer completely. Firebird and Thunderbird are enough faster than Explorer and Express to offset some of the sluggishness you get with a 466 Celeron and XP.
Explorer isn't really hidden too well -- clicking on Windows Update brings up an Explorer window. But Windows Update only runs in the Explorer browser, even though it would be straightforward enough to make it browser independent. That's not the Microsoft way, though.