Firefox 2, Internet Explorer 7. The latter is going to be distributed to all windows users, and its market penetration will be high only because of that. Please note that "If you decide to install IE7, it will preserve your current toolbars, home page, search settings, and favorites and installing will not change your choice of default browser". And the original IE6 UI ??-) or will users have to cope with what I think is the biggest UI failure ever in the Microsoft world ?

All in all, my opinion did not change ; IE7 is far behind FF2.