There are all kinds of tea available right now, but they will only taste great if you brew them properly. Using the wrong technique on the best of teas can turn something delicious into something that tastes like dirty dishwater.
Black teas are the most robust. Their rich, astringent flavor can be enjoyed on its own, or with milk and sugar (such as English or Irish Breakfast), or with lemon (such as Earl Grey). Black-teas generally contain about half the caffeine of coffee, but decaffeinated options are very common now and usually quite tasty.
Black-teas consist of dried and cured leaves, so it takes a good amount of effort to get the best flavor out. It should be steeped in boiling water for four to six minutes for the most flavor, or three to four for a slightly milder flavor. To tell if it is done brewing, watch for individual leaves to uncurl (if using loose leaf) or for the water to turn a uniform color without stirring (if using bags).
Green tea has become quite popular lately, probably due to the sheer abundance of flavors readily available. From the smoky, over-the-top Gunpowder, to the delicately floral jasmines, green-teas are a wonderful option for those who want all the depth of flavor but even less caffeine than black.
Green-tea is ruined by water that is too hot, and will lose its delicate green color and wonderful flavor. If the green comes out yellow, the water you used is too hot, and you should start over. Water should be well under boiling (160 degrees F or less). A good rule of thumb is to let your water cool until you just stop seeing steam come off of it. Brew green-teas for 3 to 4 minutes, and you can reuse your leaves to brew another pot.
White teas are a newer option, and have less caffeine than green (almost none) with even more subtlety. White-tea can handle slightly hotter water than green (just below boiling), and should steep for 4 to 6 minutes.
Herbal teas come in countless flavors, and many claim to have health benefits. Chamomile is light in flavor and supposedly relieves stress. Mint flavored is said to be good for the stomach. Fruit blends such as lemon or orange purportedly give you a non-caffeine kick and provide vitamin C. Herbal tea should always be brewed according to directions, but in general they should be brewed for a longer time but a lower temperature (below boiling) to unlock the most flavor.
Tea is a delightful way to enjoy something truly good for you. It takes a little practice, but the best cup of tea is brewed when you slow down and take time to do it for yourself.