Romantic & Evocative:
* Crimson Embrace
* Moonlit Masquerade
* Eternity's Kiss
* A Thousand Crimson Years
* Shadow of Forever
* Whispers of the Night
* The Undying Heart
* Blood and Roses
* Fangs and Flowers
* Midnight Bloom
Dark & Mysterious:
* The Obsidian Covenant
* Crimson Debt
* The Vampire's Requiem
* Shadow of the Crimson Moon
* A Taste of Immortality
* The Price of Forever
* Forbidden Blood
* The Night's Embrace
* Death's Sweet Song
* The Devil's Bargain
Intriguing & Unique:
* The Hemlock Heart
* The Last Sunrise
* Echoes of the Tomb
* A Bite of Heaven
* The Pale Embrace
* Crimson Legacy
* Stardust and Shadow
* The Unhallowed Union
* The Serpent and the Sun
* The Gilded Cage
Simple & Direct:
* Vampire's Love
* Bloodline
* Immortal Heart
* Eternal Love
The best title will depend on the specific tone and plot of your story. Consider what aspect of the story you want to emphasize – the romance, the darkness, the conflict, or the uniqueness of the characters.