My favorite green tea is toasted rice green tea. I had to choke down enough costs-as-much-as-a-car-tea-ceremony-green-tea at diplomatic functions and holidays with a smile on my face to really loathe the stuff. Gack. Don't get me wrong, I can still drink it with a smile on my face, and we still have some of it... but I wouldn't do it on purpose, unless it was to avoid being impolite. Fortunately, it's almost impossible to find in the states, but some temples DO keep a stock of it for weddings and such. Toasted rice green tea is NEITHER expensive, nor frothy (ick), but suits me down to the ground.
Green tea, traditionally (japanese traditionally, at least, can't speak for china) is drunk straight, hot or chill, but never cold... unless you're buying a bottled drink of some kind with tea in it. There are dozens of varieties, and any flavoring is type specific to the tea (like toasted rice, pine resin, etc.). One does not add sweetener, and dairy is practically non-existent in Japan.
For black Teas... I like PG tips. With sugar ( quite a lot), and cream sometimes. .. and dearly love southern sweet tea, with just a pinch of baking soda