DISQUS

I like TwetDeck, I did have issues with the earlier version taking up so much screen space but the latest build does have a 1 column view that I think improves it greatly. Just click on the small box with "1" on it in the top right corner next to the "minimize" button and you are away! Just slide the bottom bar along to view your other columns.

"Piqued" your interest. Just sayin'. ;-)

I run Facebook as a full page in its own tab on iGoogle, you can read how to do that on my blog.

"The only difference here is that my other contacts can access my page."
Google docs and Calender are set up to be multi user.
If you want to share e-mail or anything else on iGoogle all you have to do is set up a new e-mail account named for whichever project and just run it from there, then you can share the password with whoever else may be participating.

I use iGoogle and find it does just about everything you need it to, especially if you use your tabs.
I wrote a post that looks at using iGoogle to increase productivity.
I have even added my Facebook account in its own tab, so I don't ever need to leave the page!

Seems like a great project, I am enjoying reading all the different tips, yet another way for me to avoid any actual productivity! ;-)
I look forward to reading the e-book.