In case you haven’t noticed, WordPress 2.8.1 is now available for public consumption. This update fixes a number of issues people were having with 2.8 such as the visual editor disappearing and automatic core upgrades not deleting certain files causing various things to break. This release also contains extra security that has been put in place to better protect you from plugins that do not do explicit permission checks.
You should see the upgrade notification already in your dashboard.