Google has introduced Reader, a web based RSS tool. You can view content from RSS feeds within Reader and also have the option of subscribing to sites. I pretty much use NetNewsWire on my laptop as my RSS reader, but I do use Bloglines when traveling or away from my computer.
I just started playing around with it but so far looks pretty interesting. You can search Google for content and view posts in the Reader interface. You can also subscribe to sites. The interface looks a bit like GMail. It also has a tagging feature. Should be interesting to watch as this develops. This makes me think I won't be using Bloglines much anymore...