There are a ***lot*** of different types of green tea, too. Chinese and Japanese varieties in general taste very different (Indian teas tend to be more like Chinese tea), but even so, there's a huge range of flavors and mouth feel - and caffeine content, too.

I'm not an enormous fan of Teavana, but they will let you sample the aromas of any tea on the shelf, plus they usually have several for tasting. You could also sample aromas if you have an Asian grocery with bulk bins.