I've mocked up my own little life stream, tracking my Twitter, Flickr, Del.icio.us, Last.fm, and blog posts. It's a quick 'n' dirty script that isn't doing any caching. The important thing is that it's keeping the context of the permalinks (song, link, photo, or blog post) and displaying them ordered by date and time. What I'd really like to do is display the same information in a more time-based interface: a calendar, or timeline.
I really like the concept of Jermey Keith's Lifestream, and after reading Mike's cry in the dark for something akin to this, that caches, I decided to create a plugin/page template combo that replicated Jeremy's code, but using only bits and bots that are present in WordPress.