As ‘buzzword’ as that sounds, that’s basically what I’m building for myself. It’s got an integrated bookmark manager, basic email features, news aggregation, calendar, file management, plus to-do list and sticky notes (via web-form or email thanks to the power of blosxom!).
It’s framed like crazy, but will include some cool DHTML tools and things to make it easier to use and more friendly. I’m basing as much as possible on XML/XSL as well, so that is proving to be interesting. I already have a basic version of the sticky notes and to-do list features working (ugly, but operational) and that’s using XML and XSL exclusively (coming from a blosxom backend!)
I hope to build it so that it’s easy to add new tools/features into it, and that it can provide a useful point for me to start whenever I get online, since it’ll be accessible from anywhere, and have access to most things I need!.