I'm fairly slow to anger so I don't experience it much but when I do I tend to stay angry (in an active state) for anywhere from 15 minutes to maybe 2 hours. That said I don't necessarily feel peaceful or even neutral towards the person with whom I am angry until some sort of resolution is achieved.
And with one particular person in my life I found myself being angry everytime I saw him for a couple of weeks. I hated feeling that way but felt very betrayed and frustrated and I guess that was the easiest reaction in the beginning.