I am the same way.
I can drink coffee all night and still go to bed when my head hits the pillow.
I don't really drink coke or any other sodas at all.
One night I went on a trip with some friends and we all met at someone's house for the weekend. I had had a rough week at work, and was tired as hell when I flew in Friday night. All i wanted to do was go to bed, i had been up since 5:30 for a 15 miler and full day of work.
Needless to say I was going out with my friends, so we all did a jaeger(sp?) bomb right out of the gates.
That one stupid Red Bull kept me up all night.
I sat in bed from like 3am until 9am and could not sleep. Nothing has ever done that to me before. Everyone else slept until like noon, so at 9:00 I just went running.