Disclaimer: This is an application that I developed, but I got permission to post this by asking email@example.com first.
Feed Notifier is a Windows application that resides in the system tray and displays pop-up notifications on your desktop when new items arrive in your subscribed RSS or Atom feeds.
I personally use it to track all of my favorite Stack Overflow tags. I'm sharing it here because I think you guys might find it useful for the same purpose. Here's what it looks like:
From Feed URL: http://stackoverflow.com/feeds/tag/python
This is not like a normal RSS reader in that it gives you near real-time, transient notifications. If you see a headline pop up that isn't interesting, just ignore it and you won't see it again. If you like it, click the link to launch it in your browser.
I often am able to get an answer in first because this app lets me see it very soon after it was asked.
Stack Overflow (and the rest of the trilogy) have RSS feeds all over the place so you can subscribe to just those things you are interested in. However, you can also add keyword filters to the application to inclusively or exclusively filter the popups. That can be useful if you find the application too distracting (I don't use them myself).
I also use the app to see Subversion commits as soon as they occur by subscribing to the TRAC timeline at work. I'm sure you guys can appreciate that use case as well. A full-blown RSS reader is overkill for that. I can use svn log if I need to look through a list of commits, not my reader.
I hope that this will be of use to some of you.