FWIW, I am a fringe techno person. I did dowload Firefox to use with WP and other things, and I've used it before on a 98 machine when IE simply would not go for more than 5 minutes without crashing. But I don't want my blog to only look good for technically savvy people. It's not a computer related site. My wife, for example, would never even know about anything but IE, since it came on the computer. I don't know Firefox's numbers, but last I checked my logs (for another non-computer oriented site) I think IE was over 80%.
I didn't mean to start a discussion of the merits of IE. I just think that any respectable package ought to work properly with it given the market share. Can you imagine paying money for some hosted blog service, having the layout be half garbled under IE and then getting lectured about standards when you requested tech support? That's my experience here, mostly, minus the paying part, of course ;).
If someone didn't have web programming experience and asked me about WP, I'd say to just forget it I think. I've spent a lot of time tweaking and it's still not right in IE. I'm not sure what package is out there that "just works" and allows modest customization (like changing the colors).
Again, don't get the impression that I'm angry. For the most part I'm happy with WP and really appreciate the work that I'm parasiting for free! I just would have been happier if it were a little more polished feeling, and the anti-IE thing is just frustrating because sites need to work under IE or you lose 70%+ of your readers.