I just found Google Reader today and it is WAY COOL. I've subscribed to only 3 feeds, so we'll have to see how it scales, but I'm sure it'll be fine. It's a nifty interface that I find much nicer than most of the standalone apps I've tried. Nice thing about it is I can log in and see my feeds from anywhere. Kudos!
And then while looking at some more Reader examples, I've found some other cool Ajax applications. Check these out!