Teas possess a wide variety of flavor characteristics, and sometimes a number of teas will be blended together to get a specific taste profile (think Irish or English Breakfast), or have other flavoring elements added (for example, the bergamot in Earl Gray or the jasmine flowers in Jasmine Green tea). Teas can also be blended with herbs and spices to produce truly beautiful mixtures that look a little like potpourri. These herbs may sweeten the tea (stevia), add floral notes (as in rose petals) or appeal to sense memories (orange peel and cinnamon).
But when speaking of plain, unblended tea, one of the biggest determinate of a tea's taste is the level of oxidation. You know how when you cut an apple, if you leave the cut surface exposed to air, it starts to turn brown? That's oxidation in action.
Green tea is minimally oxidised. The leaves are allowed to wither, then it is given a blast of heat to stop the process (the same way baking an apple keeps it from turning brown). The result is the retention of a more grass-like or vegetal taste. (Don't let the terms turn you off - these can be naturally sweet, refreshing cups.) Tea is harvested from the same camellia bush around three times a year. The "greenest" taste usually comes from the first growth of spring, usually called the "first flush."
Black tea is allowed to oxidize at least 75% of the way before heat is added. This results in strong, bold flavor characteristics. Black tea (though there are exceptions), tends to have more astringent elements. This has to do with tannins, the substances also found in wine that give it that "puckery" feel. This bracing quality is often incorporated into teas that are meant to be drunk at breakfast time.
In between are the oolongs, at 10%-75% oxidation. These are some of the most interesting teas, as the wide oxidation range allows them to develop any number of unique qualities. Those with less oxidation have a taste profile more similar to a green tea, while the other end of the spectrum gets you something closer to a black tea. Oolongs are often described as "earthy." You may want to try a couple of different oolongs.
The lightest tasting tea is white tea. White tea is made from the buds only (we are talking about the as-yet-to-be-unfurled leaf bud, not the plant's flower). The leaves are only allowed to wither briefly (some sources say not at all), before heat is applied to halt the oxidation. The leaves themselves can be quite beautiful with a silky down. When brewed, they usually result in a pale liquid. Some people find them almost tasteless, while others enjoy the subtle sweetness of white tea.
January is hot tea month, which is not surprising, given that it is one of the coldest months of the year. Research also suggests that tea can help your immune system, so it is only fitting that people are encouraged to add a daily cuppa or two during the height of flu season. Visit a shop that sells loose tea, if there is one in your area, and a knowledgeable tea seller may help you uncover a new favorite.