Trust scripting to connect to email. Just an HTML displayer and sound player with hooks for other apps. Built from the ground up to boot fast, be small, and run fast, and have lots of room for building stuff around it and on top of it. I think there will be sub-categories of browsers. It's too big a market to not be segmented.
Some families have two or three machines.
Different users have different needs. Now would be an excellent time for someone with a powerful brand to insert a second kind of browser into the mix, one that's fast and simple and easily extensible. Something like that for the web would do well, I think. User-driven features and no hype. It's worth looking at.