What season is it? If it's summer, 1. Spring or fall, 1 or 2. Winter is where the magic happens, and I'm probably up to 4 mugs on a good day.
I generally drink coffee for my caffeine, though, so I'm not as huge on black teas. At least half of my tea consumption technically isn't tea, either, as it's a herbal blend without any real tea leaves.
I like a good gunpowder green tea, any decent-tasting vanilla black or chai, apple herbal teas with some spice, and any sleepytime/night herbal blend that doesn't have too much mint. Mint tea can rot in hell. So can any artificially flavoured teas or floral ones that are so strong it's like drinking perfume.