WordPress 2.7
I just upgraded this site to WordPress 2.7 and everything seems to be working smoothly so far. I found a small bug in the comments system, where I kept getting an enqueue_comment_hotkeys_js(); is undefined error every time I tried to edit comments in the administration panel, but commenting out that line in edit-comments.php seems to have fixed everything up. Please let me know if anything on the site isn’t working properly after the upgrade 
I stumbled across the same issue, and found the issue to have been my FTP client. It defaulted to overwriting files if the target file (my blog) was older than the source file (the new package). This resulted in a number of files not being updated for some reason, including wp-admin/includes/comments.php which is where the missing function is located (see http://svn.automattic.com/wordpress/trunk/wp-admin/includes/comment.php ).
[...] about the function enqueuecommenthotkeys_js not being defined. A quick google showed one other victim, who also suffered, but simply commented out the call. I took a little extra time, and checked out [...]
Awesome, thanks for the tip! I just had Dreamweaver sync the whole site, it must have had the same problem with the timestamps.