While I'm in a residential area, and don't think many people would be accessing my network, I still locked it. I know I would be one of the people looking for networks if I had time, so I know others do too.

Not that I have anything worth stealing, just don't want to come home someday and find some joker thought it would be a blast to have all my printers print all day or something (as they are shared). I've also told the router which addresses to accept, for a second level.