Loose leaf black tea from Yunnan, harvested from younger buds. It's a little pricey, but it's so strong you can steep the leaves for several cups without losing much flavor. It tastes great with no add-ons, like cream or sugar.

e: Ooooh, I also like Japanese green tea, with dried orange peels, cloves, cinnamon, and cayenne flakes as an iced tea. I like it just fine as-is, but I usually add some sugar for my kids.