I've narrowed it down to when I change the pool info, but I'm using the exact same pool info as all my other Ants (Ctrl C+V right out of a spreadsheet), and cgminer isn't loading once I change the pool info. I've tried just one pool, then the other.
Weird, the Ants don't seem to like my 192.168.0.1 gateway as a dns server, which is what every other computer is set to. Set the DNS to 8.8.8.8, and now it's mining just fine.
Maybe because your router isn't a dns server/forwarder, most routers just send the isp's dns server ip's over DHCP.