@cv643d:
I so not agree with you. Next to the iMac G3 I use at the moment (the big-box Apple's monitor died) my wife runs an, rather old, AMD Duron 750 MHz with XP. I installed IE7 on it and boy... it takes like forever to load! Browsing is sooo slow.... Still makes plenty of errors on the PNG side of business and... drops into a 'error report' all to often.
On the same machine the latest version of Firefox 2 is installed. It starts faster, renders faster, responds better and... does all the PNG tricks you'd ever want (and more ;-)).
Add to that that Firefox comes with a handy debug tool for problems in HTML, CSS and JavaScript. That's far more useful than the Yellow Triangle with the 'Error in line...' comment from IE.
But then... it's a matter of taste... probably.