Formal:
* Tea aficionado: This implies a deep knowledge and appreciation for tea.
* Tea connoisseur: Similar to aficionado, suggesting a discerning palate and expertise.
Informal:
* Tea enthusiast: A general term for someone who loves tea.
* Tea devotee: Someone who is very dedicated to tea.
* Tea drinker: A simple and straightforward term.
Humorous:
* Teaholic: A play on "alcoholic" for someone who drinks a lot of tea.
* Tea fiend: Another humorous term for someone who is obsessed with tea.
Ultimately, the best word depends on the context and the level of formality you're aiming for.