Many people extol the virtues of using Google maps for genealogy. Just this week there's this blog posting and Google maps was a feature of week #7 the 52 weeks towards being a better genealogist. Sorry to be the wet blanket, but there are serious problems using Google maps which I guess no one wants to talk about.
The first is that you can't assume that a modern address is the same as an address found on a census. House and building numbers are changed over time, as well as, street names. If you plug in an address, you may in fact get something. But it may not be your ancestor's home or even where they really lived. Secondly, much of what I've seen on Google Maps is that it tries, but doesn't succeed very much in "exactness" of addresses. For instance: in the 1930 U.S. census my great-grandparents are in Westbrook, Me. at 169 Haskell Street, and my great-great-grandmother was down the street at 85 Haskell Street. That home stayed in my family throughout my youth and I spent Christmases there. It's not at 85 Haskell Street on Google Maps. It's at 108 Haskell Street. I know what the house looks like, you can't fool me. 50 years from now, you will be able to fool people.
I still think Sanborn maps and other contemporary (that means older) maps are the way to go. And most aren't yet digitized. Gasp--heresy--it's not all on the Internet yet.