One of my favorite sites using mapping is Zillow. Not everyone has been on board with the concept, but I really do think this site could be huge in a few years. Now we find out that at least in certain areas where the birds eye view is available, you can view a 45 degree angle view of the house you are interested. You can see the yard, the roof, the driveway, the neighbors, the backyard and even local parks, schools and shopping.
The biggest issue I see with this and one that I was critical about Zillow in the first place is that there is no metadata as to when the image was taken. The image could be old and not showing the true condition of the home. This is why it is still important to at least investigate houses on the ground to make sure that you are satisfied. Everyone from Ask to Zillow (Wow we can go from A to Z now with online mapping) needs to realize how important metadata is to applications and mashups.