I found a fix for my sites in which the Visual Editor was not showing.
I had been working on a posting and had the Visual Editor. I went back to the dashboard and saw the notice that there was a new WP upgrade so I upgraded. Immediately after upgrading, I went back to the same post and my Visual Editor was gone and I was stuck in the Text mode.
Knowing the there was checkbox in my profile to disable the Visual Editor, I went there and lo and behold the box was checked.
Apparently when I upgraded to WP3.5 it reset all of my users to "Disable the visual editor when writing". I simply went to the profile of each user and unchecked the box at the top of each user's page and voila the problem was resolved.