The search suggestions seem to be a bit too aggressive.
In firefox (tested in version 17 and 18), if I leave my mouse pointer somewhere just under the search box and type a search query it's replaced with whatever suggestion is underneath the pointer at the time I press enter.
In safari it seems to only happen if the mouse pointer moves, which makes it much less annoying.
Wouldn't it make more sense to only use the completion if the user clicked on the item?