While I have been (or am in the process of being) won over by gmail and even google calendar, as it is rather nice to have access to information almost anywhere, I find many of Google's apps to be rather MUCH. I waited for my invitation to Google wave, only to find out that I didn't have any friends/colleagues with which to play.
I do like the map function on google earth, as I find it much easier to locate a strange place when I know what it actually looks like, as opposed to where Mapquest tells me it should be. Too often I'm told that I can turn somewhere that I can't and a street view will let me correct that. Little things like this will help google take over the 'net (resistance is futile...)