Reeder for Mac, a Google Reader client (get it here while it’s still in beta), can display its unread count as a typical red icon badge, or it can integrate the number into the Dock icon. Go to Reeder > Preferences > General to adjust this setting.
This icon-integrated count only seems to work if you have fewer than 1,000 unread items. Once you cross that four-digit barrier, the counter gives up and displays four small boxes. This is when it’s probably a good idea to make friends with the Item > Mark all as Read option.