Just noticed that my self-hosted WP 2.8.4 (now 2.8.5) blog does not show the stats chart on the blog stats dashboard. The stats are being collected and can be viewed on wordpress.com, but not on my dashboard.
I've been auto-updating plugins for a while, so I tried deactivating WP Stats, deleting its directory, downloading 1.5.4 manually and installing it. No change.
I see others are having this problem as well. Andy, if you want admin access to debug we can make arrangements.