OK, so as usual my wading in to an issue with a slightly off-tangent comment has got adverse reactions (I can't link to the comment on Geoff's blog right now as DotnetJunkies blogs are broken...again...). What I was trying to say is that in it's current form I do think IE has reached the end of it's useful life (it has really been unchanged for more than 5 years remember!) - as a pure software product. In terms of usability, yes the competition do have a HUGE hurdle to overcome - not the least of which is the fact that it's bundled with the  OS in the first place.
Firefox is a great browser and those guys are making great leaps in their public visibility and awareness...but chances are they will never truly reach the  average user. My dearest wish is the Internet Explorer does evolve, it really needs to improve it's image in terms of spyware, security and a bunch of other stuff (which admittedly the average home user doesn't give a stuff about).
Now, I'm not saying that IE as it stands is a terribly insecure environment, with XP SP2 that just isn't true and IE is really pretty good nowadays in that respect - just most average users percieve it that way. So Internet Explorer, I'm sorry you were my true love for a long time...it's just that a prettier trendier model turned up,  but there's still hope for you! All I want is for IE to be standards compliant and enable me to work the way I want without being paranoid about BHOs or crazy ActiveX controls doing wierd stuff on my machine, let me have decent tabbed browsing (i.e., non hacked and not crashing every 10 minutes), useful extensions, nice themes (ooh...you could even support Firefox themes!) and stop crashing so often (since it is more integrated into the OS - for me IE crashing tends to mean explorer dying too - not good!) - then I'll be right back on board.
My reason for supporting Firefox so vehemently (even to the extent of parting with my hard earned cash) is partly because I think it's a great browser - and one that I WANT to use, and partly because competition seems to force MS to innovate - so PLEASE Microsoft, make IE good enough for me to want to use again!