There's one big win here I can see: your passwords don't exist in a vacuum. Many users, whether you like it or not, are going to be using the same password for a number of other websites.
By sending the hash and never letting the plaintext password hit the air, the worst that can happen is breach of your login system, you will not be responsible for someone in a coffee shop with wireshark sniffing out people's passwords, which can be applied to multiple websites.
Indeed, a scheme like hashing-in-the-browser to keep a plaintext password "off the air" is essentially a homebrewed effort to replicate a secure connection.
IE, doing this is a mistake because you may be smart but you probably haven't put your secure connection through everything that SSL has been put through.
By sending the hash and never letting the plaintext password hit the air, the worst that can happen is breach of your login system, you will not be responsible for someone in a coffee shop with wireshark sniffing out people's passwords, which can be applied to multiple websites.