I'd add three items:
- If you make music come out of my speakers unexpectedly I'll never visit your website again
- White text on black is unreadable. I can copy the text and paste it into a text editor, but there's only one d*mn white-on-black page I care enough about to do that.
- Wordpress's "snapshots" link annoyer. When you accidentally run the mouse over a link, everything stops while some utterly useless preview of the link's webpage appears in a popup. Each popup has a mechanism to disable the annoyance, but it doesn't work. I used to try to disable it every time I visited Jeff Culbreath's otherwise-fine blog, but I've given up - now I just try to navigate carefully to avoid his links since there's a penalty associated with each.