Google Reader. Summary: nice way of reading your favorite blogs and news sites. Keyboard short cuts are great.
The less good bits: no way to mark all posts as read, usefuil if haven’t read for a couple of days. Also very slow to add a number of feeds at once. Add each feed takes five or so clicks, and you end up back at your Google Reader homepage, and so have to repeat process all over again.
Finally, there seems to be a whole load of stories that are never marked as read for me, and currently constantly sitting at the top of my ‘to be read list’. annoying.