Now, *this* Thing is far more my style. I admit to being fascinated by productivity methods, and had already tried out many of the sites listed (and am looking forward to trying Scrybe when it opens for registration again.)
I admit I don't usually use them much. At home, my start page is my LiveJournal friends page (which is the one I want to recheck most often.) At work, we have an automatic start page of the school website. I do have an iGoogle page set up (the tool I use most is the weather forecast).
I go back and forth between different sites. My current favorite for lists of concrete tasks (things I want to write about, things I want/need to buy) is Gubb - it will let you set up lists and check things off in a way I find visually attractive and easy to use. I also like that I can move items around easily (so, for example, in my 'books to buy' list, I
A friend recently reminded me of Hiveminder which will let you tag tasks and sort them. I find the entry mechanisms easier for me (personally: this is such a quirky type of thing) than Stikkit or some similar sites, and I really like the Task Review option (where it runs you through all tasks you have listed.)
I tend to prefer lots of little separate lists, rather than one big long one for a project, which has made something like Hiveminder or Gubb a better fit for me than Backpack (whose set up tends to focus on larger projects).
There are times I've found productivity sites don't always work well for me. For example, I keep a pretty extensive list of books I'm somewhat interested in reading (browsing Booklist for work tends to have that effect on me.) The thing is, I am not likely to have a computer handy when I go to the library, and I often get reminded of books while I'm at places where I don't have a computer (talking with friends, for example.) And as I don't have a PDA and my cell phone does not have a large data plan (and besides which, it's slow), that's a problem.
I've found keeping my 'want to read' lists on the computer doesn't work that well for me, as a result - I kept having to spend too much time transferring stuff from a paper note to the computer, or writing down things I was interested in browsing for ('What stuff on my list is actually on the shelf right now? I'll get that' is a fairly common thing for me) from the computer. Keeping it all on paper turned out to be easier (though it makes tracking what I've actually read somewhat trickier, as that's something I prefer to do on computer.)
The real thing I've taken away from productivity sites is how varied they are - there have been sites I thought I'd love that turned out not to be as good a fit for my actual use, and sites that I wasn't sure would work for me that turned out to be fantastic fits for some uses. (Gubb's actually one I wasn't sure about at first...)