Google docs. I already use Google calendar to keep track of comings and goings in my house. I've been using it for a couple of months now, and find it helpful. It's great to be able to check it at work when I want to see what's happening.
I tried Zoho also, and created a nifty to-do list (time to make the Christmas pudding and refine the address list for writing Christmas cards). I think I will keep the list up, it's possible that being able to access it quickly from any computer might be helpful. I'll see (ask me after Christmas if I feel more organized!)
While I think that these applications could be useful for people who don't have access to the commercial products, I think that most people who are savvy enough to know about them and use them undoubtedly have Microsoft Office also.
I will keep them in mind if I need to have a document that other people could collaborate on with me (I needed this last week when I was working on homework for the ABS training!)
Posting to my blog from Google Docs is a snap. It's easier to work with images with Google docs, but uploading from a file on my computer doesn't seem to work. Somehow in the process of uploading the .jpg gets removed, and then of course I get a message saying 'the file is not in the correct format'. All of this is somewhat frustrating and time consuming, but then this often happens while exploring new applications. One of things I know about exploring all of these wonderful things is that you have to expect it to be frustrating sometimes, and not everything will work the way you expect it to. AND, you have to expect to spend a little time with it to get it right.