Recently discovered Yerba Mate from a Brazillian friend. It's supposedly really good sweet and with ice but haven't tried it yet (as we are in the depths of winter).
Matcha tea is supposedly the best tea in the world, comes in green powder form, supposedly has x8 times more anti-oxidants, it's used in Japanese tea ceremonies, a lot of Buddhist monks drink it because apparently it is very mind stimulating but does not have the physical caffeine "jerks" and only lasts 6 hours. You can make it in a latte too which is delicious.
Chai in India for 2 rupees sold outside bus stands = amazing. Assam is great there too, naturally.
Earl Grey = Captain Picard tea, has a natural fruity flavour to it.
Don't start me on herbal teas: I did a herbalist course last year.
My favourite insomnia mix: St. John's Wort, Valerian, Skullcap, Chamomile, Lavender.
Echinacea good all-rounder for immune system.