https://support.mozilla.com/en-US/forum/1/531033?forumId=1&comments_threshold=0&comments_parentId=531033&comments_offset=40&comments_per_page=2… (read more)
describes several ways to get rid of the Bing toolbar, but none of these helped. In particular, I don't have any addon named Bing, or Search Toolbar, and I haven't anything of that name installed on my PC.
Note that I am not talking about the search to be performed when entering something in the address bar (this I could get back from Bing to Google), but about the additional Bing Searchbar, which is just useless and takes away screen space. You can see a screenshot here:
The search bar I'm talking about, is the third bar from top, having the word SEARCH in uppercase.
I'm running Firefox 3.6.3 on Windows 2000.
== I think it started when I upgraded Firefox to the current version