It’s out.

Sadly, the Blocksite addon does not work in 3.5, which means the return of the horrible Google Suggest feature (now even worse because it’s started including “Sponsored links in suggestions”). To turn off Google Suggest completely and for good, instead use the Adblock Plus addon, and in its ‘Options/My Adblocking Rules’ simply block the domain:

This is the server handling the Google suggestion keywords. Blocking it turns off Google Suggest, with no other ill effects.