Nice, simple script that's almost perfect, but has two minor issues.

The first is that it still leaves a tiny grey line where the ad was. Changing "innerHTML" to "outerHTML" in the script will make it remove the ad completely.

The other is that it doesn't work using http (not all international google pages default to https yet). Changing "https" to "http*" in the include line will fix this.

Great script, will do what it says, but if you're using any of the international google localizations it won't do squat unless you get into the script.

My work-around was to change the include line.
Original:
// @include https://www.google.com/

My change:
// @include https://www.google.*/

I've wildcarded the .com, so it would trigger on all TLD's.
But I can't be sure if there won't be situations where this ends up biting me in the ass, it's just a quick dirty fix.
Possibly it's better to just add more includes for each locale, but I'm too lazy to go there right now :p

Anyway, great script, small script, simple script that will work, provided you either use the .com version of google or change the include.