If you want to reliably beat CB, Elspeth is your card. Fireblast suffers from 3-for-one-yourself syndrome. While great at getting around a CB, any other counter spell ruins your day. Elspeth, OTOH, is amazing. Four gets around CB almost as well as 6, provides a continuous source of creatures and evasion pumps to get around their Wall of Goyf. Vendillion Clique is typically their only way to deal with Elspeth and Clique is fairly easy to deal with.