I only drink coffee, no sodas or caffeinated teas. I have noticed that now that I am not drinking I am more sensitive to the caffeine as I have less to balance out I would guess.
I drink about 2 cups of percolated Italian style coffee in the morning (I think it would be like ordering a cafe latte at starbucks). Very occasionally I will have an espresso after lunch, I'd say once every couple of weeks. Very, very rarely I have one after dinner. Generally I cannot drink any caffeine after 16:00 or I can't sleep, this was also when I was drinking heavily.
When I was drinking I drank much more coffee, probably 2-3 cups in the morning and maybe 1 or 2 more throughout the day.
I haven't thought too much of the negative aspects of caffeine, I suppose I should. I am more worried about sugar, which I eat little of but don't deny myself.
Several years ago I cut out the sugar in my coffee. The first day it was horrible. The very next day, it was ok. By the third day it was great and I could never go back to drinking coffee with sugar in it. I couldn't believe how easy it was to cut out those daily spoonfuls.