Do listen to a few and choose one you feel drawn to.

    Namo Amida Bu
    Amitabha
    Namo Quan Shi Yin Bosat
    Om Mani Padme Hum Hrih
    Om Ami Dewa Hrih

    Some other recordings of liturgy

    Prajnaparamita Hridaya Sutra p20 (the text is wrong in places – I learnt this using the resources here & here)
    The Heart Sutra in Japanese
    Tai Shih Chih Prayer