I'm not sure if cox still requires it, but did you put in the hostname that the install technician gave you when you first got @home? Mine was something like cx619232-z or something. The dhcp server wouldn't assign you an address unless it was set right. So make sure that your hostname is set correctly. I can't get more specific because I use a cable router/firewall type thing and it handled the switch transparently to me.
And it's normal to detect your NIC as a 3c59x. That's the driver module for both 3c590's and 3c905's.