I would have to say Google beats all others.
Nowadays it's not 'look for it on the internet', but google this or that. They have gone from a company name to mean much more to the lives of people worldwide. They have taken over the internet and didn't cost them much.
This can turn out to be a problem. When specific brands are made generic (e.g. hoover, qtips, pampers, vaseline, bandaids) they can get forgotten in competition. They may still hold a good position but it seems more out of inertia than anything.