Ever since the valour mechanic was introduced, I've been longing to play a deck that actually felt like I was making frequent use of the valour keyword, rather than just a generic high-threat deck that occasionally uses a special action.
Much to my satisfaction, in the last game I played with this deck, I felt I was interacting with the valour mechanic in some fashion nearly every turn, including more than one use of a game-saving valour effect. So I decided it was time to share.
Mulligan for Legacy of Númenor or The Seeing-stone. With those cards, along with the treat-raising effects of Hirgon and Steward of Orthanc, getting to 40+ threat is easy.
From there, maintaining your threat in the 40-49 range is done with Gandalf and Favor of the Valar.
Use the huge amount of resource acceleration from Legacy of Númenor, Mablung, Théodred, and Hirgon to dump out cards on the table.
Your primary defender to set up will be Defender of Cair Andros with a Spear of the Citadel and a Hauberk of Mail so that he'll be defending for 5 and retaliate for 2 direct damage. Any damage he does take should be minor and easily cancelled with Honour Guards. Finish off enemies with Marksman of Lórien and your eagles.
Fierce Defense and Horn's Cry are your emergency buttons. Their valour actions can completely turn around a tight situation, whether by simply discarding a mumak from play or allowing you to take a whole string of attacks undefended.