I've recently installed Easy Page Link for WPML onto a colleague's WordPress site and took immediate notice of the visual editor on the post/page Write Screen being turned off. There seems to be no effect on the HTML editor, however.
I have run this test with other plugins enabled, but none which tinker with the write screen editors to my knowledge. After disabling the Enable Page Link for WPML I discovered my visual editor returns.
For now I have decided to disable this plugin because use of the visual editor is important. The installation is running WordPress 3.0 by the way.