The 2.7 admin menu top level items overlap the page content when the browser is set for font sizes larger than 12px. There are two ways to fix this.
One (the way the developers should now please take) is to go to wp-admin.css, scroll down the line that says "#adminmenu a.menu-top" and change "min-width: 10em" to "min-width: 100px".
The other is to use a plugin to add the pixel min-width. Download it here.
One line! One measly line! Oh my jesus fucking god, you people! Now that I have done your one piddly line of accessibility work for you, can we hope that this will be included in the next release? This problem has only been pointed out how many times?
*is utterly disgusted* WordPress is starting to really remind me of LiveJournal.