All I drink (regularly) is tea & water. Both the tea & the preparation (temperature of the water + seep time) make a difference.
I buy loose leaf and use either french presses, tea presses, or a fancy teamaker that my gf has to brew the tea.
My go-to supplier is Peets (
www.peets.com) and their loose-leaf teas. My favorite is a simple gundpowder organic tea. I also really like their Assam golden tip (black tea) and their Masala Chai. When I go to farmer's markets I buy some other varieties and when we were in Vancouver last month we bought some David's tea (a franchise in Canada and maybe the northern states). Some local places here also sell some good blends and we have some herbal teas (no caffeine) that we make at night.