Konfabulator
I knew folks who had Konfabulator installed on their OSX-based machines and enjoyed it thoroughly. I'm not going to wax philosophical on how pretty it is and all that total hooey, but it is pretty useful and does give me the ability to build information-yielding widgets that Windows otherwise doesn't have.
Right now I'm using the weather widget and the todo item widget (both ship with Konfabulator) and I stick them on my other monitor (I'm running a dual-monitor setup at work). I can glance over and see my email client, the quick todo list, and the weather outside all on one screen.
It's been really useful so far. I'm tossing around adding stock tickers, but mostly that would just stress me out. I should add a calendar widget that queries my server (where I store all my calendar information). That would be super useful.
Anyhow, it's worth looking at if you need more information at your fingertips and can spare the screen real-estate.