When thinking about ways Photosynth can best be used, helping to sell real estate came up pretty early on.  And it wasn't long before we started seeing a number of houses popping up among the synths.

Here's a great synth of a home in Colorado.

This synth of the front of a house lets you smoothly see the house and the neighborhood.

And here's a great example of how to shoot the interior of a house.

If you search on 'house' or 'real estate' you'll see lots of different ways people are shooting interiors and exteriors of houses.  Some include lots of photos, but they are not very synthy.  That's OK--if you want to concentrate on the deep zoom feature of Photosynth, having a varied collection of pictures of the different rooms in a home will still give potential buyers a close-up view that they can't get any other way (but make sure to tell them how to zoom in to get the best detail--use the + (plus) icon, or their mouse's scroll wheel).  But shooting your pictures in a way that lets them knit together better will give people the sense of traveling through the space.