When my husband and I were looking for our first home, I had strict guidelines about what I would look at. Nothing less than an acre. Period. In my mind, an acre = privacy. It was an acre, how could anyone see you in all that land? (I grew up in Levittown, so an acre sounded like a ranch to me). What I really wanted, though, was a private lot. I didn't want anyone living behind me. I wanted a treed property line. I wanted secluded privacy. Because I was focused on the wrong thing, my agent fruitlessly showed us home after home, with no chance of making us (ok..me) happy. I finally "got it" and loosened my standards a bit, and was better able to articulate what I wanted.
On my home shopping trip with Jim and Kelly the other night, we saw 5 houses. One had a huge lot. The bulk of the property was located to the side of the home, which was a corner lot. Here's a picture of the yard. Note that the corner of the front of the home is in the right corner of the picture, and if you look closely, you'll see the street outlining the yard:
Although this home had a smaller property, you'll see the difference in the yards immediately:
If you're really looking for a private back yard, make sure you don't lose focus by concentrating on acreage.