I'm not supposed to have caffeine - decaffeinated coffee is acceptable, once you're used to it, but decaffeinated tea is disgusting, so I must admit I cheat sometimes! Tea is more refreshing and thirst quenching but I drink coffee mostly.
Tea most the time, coffee when I'm having a drink out and I'm feeling weird and don't want beer.
Most sublime cuppa I've ever had is Clipper organic Earl Grey - a friend bought me a pack of 50 bags and they're going down fast! Think I'll have one now.