I am making this post regarding the key feature introduced in WordPress 2.9 "Carmen" that lets you upgrade multiple plugins at once if updates are available.
Don't you think it'd be much better to have the "Update All" button/link at "PLUGINS > INSTALLED > UPDATES AVAILABLE" instead of TOOLS > UPGRADE" ?
I needed to upgrade 4 plugins after I upgraded to WordPress 2.9 *via the Dashboard* so didn't get a chance to see the Tools > Upgrade tab! before I had almost gone crazy looking for the feature along with other plugins options.
Please consider making this change in the next maintenance release (or sooner! :-) to enhance usability..