Milk tea:
Cha chan teng (greasey spoon) tea - it's bitter, it's orange, it's the consistency of paint, and it's been brewing in that huge pot since before the British came. The crack cocaine of tea.
Taylors of Harrogate Yorkshire Gold is really the best of the blended teas. Red label Yorkshire tea comes a close second.
Although Orange pekoe (Fortnum & Mason does a good drop) is really pretty damn fine, but that's Sunday best tea.
Black or Red tea:
Bo Lei - Jolt tea, if you will. Smells like a dank basement. Wakes you up for a month or so. You can also go half-half with gok fa (crysanthemum) for the gok bo, which is very tasty.
Oolong tea:
Tiet Guun Yam (Iron Buddha) is terrific, especially the Chiu chau stuff in the little shot cups. Very dry, and pretty strong.
Shui hsin (Shui Xian) is a lovely oolong kind of thing - it's a nice in-between. Not to strong not too weak.
Green tea:
Top grade Longjing tea (top tip: this mixes great with psilocybin mushrooms - tastes good and feel no nausea).
Nasty suprise tea:
Kazakh tea. It's very good milk tea, but with salt. Ewwwww. Tibetan tea with yak butter might be worse - not sure.
World's worst tea:
Lipton's Red label. Insipid, insipid, insipid. Available all around the world, it is possibly the number one reason coffee is so popular. Only good for iced lemon tea, and even then you have to brew it for a month.