Gold Lion 12AX7 are what I've been using for the past 4 years in my preamp. Excellent performance across the entire frequency range, and won't break the bank.
http://www.cryoset.com/catalog/product_info.php?products_id=301&osCsid=7b000403923abb12045a75a9772973d7
They also make 12AT7 and 12AU7 versions of the tube.
http://www.cryoset.com/catalog/product_info.php?products_id=301&osCsid=7b000403923abb12045a75a9772973d7
They also make 12AT7 and 12AU7 versions of the tube.