Of course, users of Reeder on the other platforms will know that it is built on top of Google Reader. You log in with your Google credentials and all of your feeds (and starred items) are transfered over. But Reeder makes the experience look roughly a million times better.
Beautiful desktop app for the Mac that syncs with the (rather fugly-looking) Google Reader. I found a “Draft 1″ version here that downloaded and installed without issue. Highly recommended.