Not sure if you've seen the recent allegations of Microsoft's Bing search engine copying Google's search results. The experiment used both IE8 Suggested Sites (which defaults to "on" during setup) and Bing Toolbar.

The main concern is not so much copying of a specific website, but the fact that the experiment shows that there has to be at least the following personal information being sent:
  • URLs
  • Content on the pages visited
  • What you actually clicked on!

Given the nature of the information being transmitted, this is a huge privacy intrusion (much, much more so than e.g. a third party advertising cookie). It's all hidden in EULA's and the IE suggested sites at least is enabled by default during setup (and seems deliberately unclear so that most people will simply click "yes").

Given all that, I think that it seems like a clear candidate for something to be disabled within SpyBot S&D.

For IE8, the remedy would clearly be simply turning off Suggested Sites. Not sure what the Bing Toolbar remedy would be as I haven't got it installed (not sure if there's a setting to turn it off or not). I don't have the Google Toolbar installed either, but turning off its PageRank feature would also be recommended as it has the same sort of privacy issues.