I used to be able to drink both. There wasn't much coffee I could take unadulterated (certainly NOTHING out of Starbucks or Seattle's Best--copious cream and sugar, there, with maybe some irish creme and mint if it's strong enough to defeat the first two), but my then-local Baskin-Donuts had coffee that was worth crossing town for. The perfect roast with no acidic aftertaste, and it smelled like the dying embers of a wood fire.
Then, life intervened, and I couldn't drink coffee anymore. Sad Panda.
I took refuge in my tea collection, revelling in my personal favorite--Lapsang Souchong. It smells like a burning wood fire (which is why my mother won't let me make it when I'm visiting), and has a smooth, smoky flavor and just enough caffeine to get me through the day but not send my heart rate through the roof. My tea is my love and my consolation, and my warmth on those cold summer days when my polar-bear hubby just can't be bothered to turn up the heater.
I'm still in something of a sampling phase, but my favorite black tea has always been Lapsang Souchong. My favorite green is genmaicha (a green tea with toasted brown rice), and my favorite herbal is a lemon-wintergreen blend.
And my coffee substitute? Surprisingly, it's not the Lapsang...it's a gunpowder-style green tea with peppermint. Very strong minty smell and taste, freshens the breath while you drink it, and guaranteed to keep you awake for at least 4-5 hours. On three sips. Trust me, one mug is enough...problem is, I almost never stop at one!
(I also like a calmer mint for help getting to sleep--long story there--but the gunpowder mint is definitely my coffee substitute. Which reminds me, I need to order more of both.)