Security "guru" Bruce Schneier writes on Wired about how he runs a completely open wireless network. He thinks this is a good idea. Others disagree.
I for one, think he misses the most fundamental flaws in running an open network - the fact that strangers have access to your local network. From there, they can easily scan/exploit your local computers, brute-force your router login credentials, or poisen the ARP cache on your machines to perform man-in-the-middle attacks (to capture passwords, SSL sessions, voip phonecalls, http sessions) and so on.
Similar to the way Jeremy Clarkson didn't think anyone could do anything malicious when he posted his bank account numer and sort code in his newpaper column (he was proved wrong when monies were taken out of his account via a fraudulent direct debit), journalists quite often miss the point completely.