Ask Dr. LJ: online list keeping (attack of the OCD archivist)

I'm still in search of the ultimate to do list online.
In an ideal world it would have/be:

• Google-widget compatible.
• Particularly, fit on my work's Partnership page and allow me to log in via that Partnership account. I appear to really be Google's bitch these days. Just saying.
• Shareable

MUST have:

• multiple list function
• tagging
• note taking
• searchable

What I have used so far:
Listaculous. Didn't like the way it logged me out randomly and I couldn't see all the tabs at once. You could only delete the finished tasks- I want to track what I've done.
Google Notebook: pretty good. Has tags, easily shiftable (can move tasks from one notebook to another). The bad part Is not obviously transferable into Partnership format. Its format is also not quite great, either- too spread out across the page- too much white space. If there are keyboard shortcuts, it's not part of the FAQ.

Any thoughts from the peanut gallery on list keeping tools that might live up to my impossible standards?