Quality oolong, nothing else comes close. You don't need to add sugar, or any other flavor if you get the good stuff. Forget tea bags, and manufactured crap that comes in a box. Get the real deal.
Murchies is a chain of stores in BC that sells all kinds of teas. They've got the usual stuff plus lots of specialty teas, usually loose but also bagged I think. I think they have a mail order service but there may also be something like this in your area trading under a different name.
I don't want to butcher this but I think its called tiger balls if not dragon balls. Little balls of rolled up Jasmin that you just leave in the tea at the bottom. Proper Chinese tea, lovely jubbly.
Same deal with me - Up to about 3 months ago I drank Rockstar / Red Bull daily to get me going. I dropped that habit and started drinking green tea as well. I've been buying Salada - it's pretty good, cheap too. Like $3 or so for a box of 40 teabags I think.
also, if you don't like green tea, Welcome To Yogi has a lot of non green teas, that actually have some kick and taste to them. they give out free samples too.
Although you'll look like a total yuppie deusche you will have a great opportunity to taste a bunch of really different teas and decide for yourself...
Dilmah teas from Amazon are the best. They have 30 or 40 different ones, but my favorites are the Celyon Tea (black tea, but much better then the regular stuff) and Italian Almond Tea .