rebron’s IE 7 Competitive Analysis is worth a read. I’m glad that printing has been picked out as an area where Firefox needs future work.
It’s nice to think, as rebron suggests, that IE 7 won’t take away share from Firefox. Perhaps it won’t by converting users back directly. But it could have indirect effects; where today, if people get a new computer with IE 6, they think “Ick! Install Firefox now!”, if it comes with IE 7, they may just live with it. Also, people often install Firefox for their relatives or friends – will they be as eager to do so when the feature/usability gap is smaller?
I guess the answer to that is, let’s keep that gap wide :-)