I'm using IE 6.x with WinXP. Quick, other than tabbed browsing, top reasons to bother with FireFox...
And not its logo either - which I think is phenomenal and somehow entrancing.

I do know that I'd be giving up my excellent Google bar at its custom settings for what looks like some cheap imitation (does it only allow Feeling Lucky searching?)
Also, is there a link with screenshots for Windows? If you want to get a browser war going, you need screenshots. Why so many application developers don't understand this is beyond me. I do mean shots that are bigger than thumbnails - I saw plenty of those stamp[-sized cut-outs on their "What's New" pages.
Bruno