Personally I'm a BIG fan of the Red Seal "Black Adder" liquorice tea. I have a huge sweet-tooth, and usually have to add heaps of sugar, but this one is wonderful as-is. It's sweet and it smells glorious. It's also quite tasty hot or cold, which works for someone like me who forgets I have a cup of tea sitting next to me on my desk. I tend to leave the bag in, as it doesn't go bitter. I find it really good as a pick-me-up, and it's great if you're feeling a bit sick as well (just as an aside).
Heh, I'm a bit of a tea-snob, so the only drawback about this tea is that it is in bag form, but it's tasty enough for me to overlook this fact.
If you're interested, here in New Zealand it's "flavour"
Edit: also, I feel compelled to add that this isn't, technically, a "tea" it's an infusion, since "tea" only refers to the infusions made from leaves of the tea plant. Did I mention I'm an incurable tea snob, and avoiding doing my uni essay? :p