I just upgraded two blogs to WP 2.5 and everything seems to be fine (knock on wood) save one issue:
Before the upgrade, the login screen on both sites was nicely styled in the default WP login style. But now the login screen for both blog admins are missing all formatting. I didn't make any changes to the theme (the default for the admin or the public theme itself post-upgrade).
Any idea what's going on, or better - how to fix?