When designing a site with a fixed width, do you ever take the size of a bookmarks bar into consideration? For example, when designing for 1024×768 screen resolution, do you limit your site’s size to 800px to accommodate a (possible) bookmarks bar on the side?
Personally, I never browse with bookmarks on the side, but I haven’t been able to find any stats on this.
I agree. Don’t worry about it.
Thirded. If you start trying to accomodate every popular browser add-on or tab, you’re only in for heartache.